Photovoltaic Device Encapsulation

ABSTRACT

A photovoltaic device comprising a first electrode, a second electrode, an active layer disposed at least partially between the first and second electrodes, an interfacial layer disposed at least partially between the first and second electrodes, and a non-stoichiometric oxide layer disposed at least partially between and in contact with one of the first or second electrodes and an encapsulant layer. The active layer of the photovoltaic device comprises a photoactive material.

BACKGROUND

Use of photovoltaics (PVs) to generate electrical power from solarenergy or radiation may provide many benefits, including, for example, apower source, low or zero emissions, power production independent of thepower grid, durable physical structures (no moving parts), stable andreliable systems, modular construction, relatively quick installation,safe manufacture and use, and good public opinion and acceptance of use.

Portions of PVs may be susceptible to oxidation or corrosion bysubstances present in the environment. PVs may function better ifprotected from environmental oxidation or corrosion.

The features and advantages of the present disclosure will be readilyapparent to those skilled in the art. While numerous changes may be madeby those skilled in the art, such changes are within the spirit of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of DSSC design depicting various layers of theDSSC according to some embodiments of the present disclosure.

FIG. 2 is another illustration of DSSC design depicting various layersof the DSSC according to some embodiments of the present disclosure.

FIG. 3 is an example illustration of BHJ device design according to someembodiments of the present disclosure.

FIG. 4 is a schematic view of a typical photovoltaic cell including anactive layer according to some embodiments of the present disclosure.

FIG. 5 is a schematic of a typical solid state DSSC device according tosome embodiments of the present disclosure.

FIG. 6 is a depiction of components of an exemplar hybrid PV batteryaccording to some embodiments of the present disclosure.

FIG. 7 is a stylized diagram illustrating components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 8A is a stylized diagram illustrating a hybrid PV battery accordingto some embodiments of the present disclosure.

FIG. 8B is an electrical equivalent diagram relating to a hybrid PVbattery according to some embodiments of the present disclosure.

FIG. 9 is a stylized diagram showing components of an exemplar PV deviceaccording to some embodiments of the present disclosure.

FIG. 9A is a stylized diagram showing components of an exemplar deviceaccording to some embodiments of the present disclosure.

FIG. 10 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 11 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 12 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 13 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 14 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 15 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 16 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 17 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 18 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 19 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 20 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 21 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 22 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 22 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

FIG. 24 is a stylized diagram showing components of an exemplar PVdevice according to some embodiments of the present disclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Improvements in various aspects of PV technologies compatible withorganic, non-organic, and/or hybrid PVs promise to further lower thecost of both organic PVs and other PVs. For example, some solar cells,such as solid-state dye-sensitized solar cells, may take advantage ofnovel cost-effective and high-stability alternative components, such assolid-state charge transport materials (or, colloquially, “solid stateelectrolytes”). In addition, various kinds of solar cells mayadvantageously include interfacial and other materials that may, amongother advantages, be more cost-effective and durable than conventionaloptions currently in existence.

The present disclosure relates generally to compositions of matter,apparatus and methods of use of materials in photovoltaic cells increating electrical energy from solar radiation. More specifically, thisdisclosure relates to photoactive and other compositions of matter, aswell as apparatus, methods of use, and formation of such compositions ofmatter.

Examples of these compositions of matter may include, for example,hole-transport materials, and/or materials that may be suitable for useas, e.g., interfacial layers (IFLs), dyes, and/or other elements of PVdevices. Such compounds may be deployed in a variety of PV devices, suchas heterojunction cells (e.g., bilayer and bulk), hybrid cells (e.g.,organics with CH₃NH₃PbI₃, ZnO nanorods or PbS quantum dots), and DSSCs(dye-sensitized solar cells). The latter, DSSCs, exist in three forms:solvent-based electrolytes, ionic liquid electrolytes, and solid-statehole transporters (or solid-state DSSCs, i.e., SS-DSSCs). SS-DSSCstructures according to some embodiments may be substantially free ofelectrolyte, containing rather hole-transport materials such asspiro-OMeTAD, CsSnI₃, and other active materials.

Some or all of materials in accordance with some embodiments of thepresent disclosure may also advantageously be used in any organic orother electronic device, with some examples including, but not limitedto: batteries, field-effect transistors (FETs), light-emitting diodes(LEDs), non-linear optical devices, memristors, capacitors, rectifiers,and/or rectifying antennas.

In some embodiments, the present disclosure may provide PV and othersimilar devices (e.g., batteries, hybrid PV batteries, multi junctionPVs, FETs, LEDs etc.). Such devices may in some embodiments includeimproved active material, interfacial layers, and/or one or moreperovskite materials. A perovskite material may be incorporated intovarious of one or more aspects of a PV or other device. A perovskitematerial according to some embodiments may be of the general formulaCMX₃, where: C comprises one or more cations (e.g., an amine, ammonium,a Group 1 metal, a Group 2 metal, and/or other cations or cation-likecompounds); M comprises one or more metals (example s including Fe, Co,Ni, Cu, Sn, Pb, Bi, Ge, Ti, and Zn); and X comprises one or more anions.Perovskite materials according to various embodiments are discussed ingreater detail below.

Photovoltaic Cells and Other Electronic Devices

Some PV embodiments may be described by reference to variousillustrative depictions of solar cells as shown in FIGS. 1, 3, 4, and 5.For example, an example PV architecture according to some embodimentsmay be substantially of the form substrate-anode-IFL-activelayer-IFL-cathode. The active layer of some embodiments may bephotoactive, and/or it may include photoactive material. Other layersand materials may be utilized in the cell as is known in the art.Furthermore, it should be noted that the use of the term “active layer”is in no way meant to restrict or otherwise define, explicitly orimplicitly, the properties of any other layer for instance, in someembodiments, either or both IFLs may also be active insofar as they maybe semiconducting. In particular, referring to FIG. 4, a stylizedgeneric PV cell 2610 is depicted, illustrating the highly interfacialnature of some layers within the PV. The PV 2610 represents a genericarchitecture applicable to several PV devices, such as perovskitematerial PV embodiments. The PV cell 2610 includes a transparent layer2612 of glass (or material similarly transparent to solar radiation)which allows solar radiation 2614 to transmit through the layer. Thetransparent layer of some embodiments may also be referred to as asubstrate (e.g., as with substrate layer 1507 of FIG. 1), and it maycomprise any one or more of a variety of rigid or flexible materialssuch as: glass, polyethylene, PET, Kapton, quartz, aluminum foil, goldfoil, or steel. The photoactive layer 2616 is composed of electron donoror p-type material 2618, and/or an electron acceptor or n-type material2620, and/or an ambipolar semiconductor, which exhibits both p- andn-type material characteristics. The active layer or, as depicted inFIG. 4, the photoactive layer 2616, is sandwiched between twoelectrically conductive electrode layers 2622 and 2624. In FIG. 4, theelectrode layer 2622 is a tin-doped indium oxide (ITO material). Aspreviously noted, an active layer of some embodiments need notnecessarily be photoactive, although in the device shown in FIG. 4, itis. The electrode layer 2624 is an aluminum material. Other materialsmay be used as is known in the art. The cell 2610 also includes aninterfacial layer (IFL) 2626, shown in the example of FIG. 4 as a ZnOmaterial. The IFL may assist in charge separation. In some embodiments,the IFL 2626 may comprise an organic compound according to the presentdisclosure as a self-assembled monolayer (SAM) or as a thin film. Inother embodiments, the IFL 2626 may comprise a multi-layer IFL, which isdiscussed in greater detail below. There also may be an IFL 2627adjacent to electrode 2624. In some embodiments, the IFL 2627 adjacentto electrode 2624 may also or instead comprise an organic compoundaccording to the present disclosure as a self-assembled monolayer (SAM)or as a thin film. In other embodiments, the IFL 2627 adjacent toelectrode 2624 may also or instead comprise a multi-layer IFL (again,discussed in greater detail below). An IFL according to some embodimentsmay be semiconducting in character and may be either p-type or n-type,or it may be dielectric in character. In some embodiments, the IFL onthe cathode side of the device (e.g., IFL 2627 as shown in FIG. 4) maybe p-type, and the IFL on the anode side of the device (e.g., IFL 2626as shown in FIG. 4) may be n-type. In other embodiments, however, thecathode-side IFL may be n-type and the anode-side IFL may be p-type. Thecell 2610 is attached to leads 2630 and a discharge unit 2632, such as abattery.

Yet further embodiments may be described by reference to FIG. 3, whichdepicts a stylized BHJ device design, and includes: glass substrate2401; ITO (tin-doped indium oxide) electrode 2402; interfacial layer(IFL) 2403; photoactive layer 2404; and LiF/Al cathodes 2405. Thematerials of BHJ construction referred to are mere examples; any otherBHJ construction known in the art may be used consistent with thepresent disclosure. In some embodiments, the photoactive layer 2404 maycomprise any one or more materials that the active or photoactive layer2616 of the device of FIG. 4 may comprise.

FIG. 1 is a simplified illustration of DSSC PVs according to someembodiments, referred to here for purposes of illustrating assembly ofsuch example PVs. An example DSSC as shown in FIG. 1 may be constructedaccording to the following: electrode layer 1506 (shown asfluorine-doped tin oxide, FTO) is deposited on a substrate layer 1507(shown as glass). Mesoporous layer ML 1505 (which may in someembodiments be TiO₂) is deposited onto the electrode layer 1506, thenthe photoelectrode (so far comprising substrate layer 1507, electrodelayer 1506, and mesoporous layer 1505) is soaked in a solvent (notshown) and dye 1504. This leaves the dye 1504 bound to the surface ofthe ML. A separate counter-electrode is made comprising substrate layer1501 (also shown as glass) and electrode layer 1502 (shown as Pt/FTO).The photoelectrode and counter-electrode are combined, sandwiching thevarious layers 1502-1506 between the two substrate layers 1501 and 1507as shown in FIG. 1, and allowing electrode layers 1502 and 1506 to beutilized as a cathode and anode, respectively. A layer of electrolyte1503 is deposited either directly onto the completed photoelectrodeafter dye layer 1504 or through an opening in the device, typically ahole pre-drilled by sand-blasting in the counter-electrode substrate1501. The cell may also be attached to leads and a discharge unit, suchas a battery (not shown). Substrate layer 1507 and electrode layer 1506,and/or substrate layer 1501 and electrode layer 1502 should be ofsufficient transparency to permit solar radiation to pass through to thephotoactive dye 1504. In some embodiments, the counter-electrode and/orphotoelectrode may be rigid, while in others either or both may beflexible. The substrate layers of various embodiments may comprise anyone or more of: glass, polymer, polyolefin, polyethylene, polypropylene,PEN, PET, PMMA, polycarbonate, Kapton, quartz, sapphire aluminum, silverfoil, gold foil, wood, concrete, and steel. In certain embodiments, aDSSC may further include a light harvesting layer 1601, as shown in FIG.2, to scatter incident light in order to increase the light's pathlength through the photoactive layer of the device (thereby increasingthe likelihood the light is absorbed in the photoactive layer).

In other embodiments, the present disclosure provides solid state DSSCs.Solid-state DSSCs according to some embodiments may provide advantagessuch as lack of leakage and/or corrosion issues that may affect DSSCscomprising liquid electrolytes. Furthermore, a solid-state chargecarrier may provide faster device physics (e.g., faster chargetransport). Additionally, solid-state electrolytes may, in someembodiments, be photoactive and therefore contribute to power derivedfrom a solid-state DSSC device.

Some examples of solid state DSSCs may be described by reference to FIG.5, which is a stylized schematic of a typical solid state DSSC. As withthe example solar cell depicted in, e.g., FIG. 4, an active layercomprised of first and second active (e.g., conducting and/orsemi-conducting) material (2810 and 2815, respectively) is sandwichedbetween electrodes 2805 and 2820 (shown in FIG. 5 as Pt/FTO and FTO,respectively). In the embodiment shown in FIG. 5, the first activematerial 2810 is p-type active material, and comprises a solid-stateelectrolyte. In certain embodiments, the first active material 2810 maycomprise an organic material such as spiro-OMeTAD and/orpoly(3-hexylthiophene), an inorganic binary, ternary, quaternary, orgreater complex, any solid semiconducting material, or any combinationthereof. In some embodiments, the first active material may additionallyor instead comprise an oxide and/or a sulfide, and/or a selenide, and/oran iodide (e.g., CsSnI₃). Thus, for example, the first active materialof some embodiments may comprise solid-state p-type material, which maycomprise copper indium sulfide, and in some embodiments, it may comprisecopper indium gallium selenide. The second active material 2815 shown inFIG. 5 is n-type active material and comprises TiO₂ coated with a dye.In some embodiments, the second active material may likewise comprise anorganic material such as spiro-OMeTAD, an inorganic binary, ternary,quaternary, or greater complex, or any combination thereof. In someembodiments, the second active material may comprise an oxide such asalumina, and/or it may comprise a sulfide, and/or it may comprise aselenide. Thus, in some embodiments, the second active material maycomprise copper indium sulfide, and in some embodiments, it may comprisecopper indium gallium selenide. The second active material 2815 of someembodiments may constitute a mesoporous layer. Furthermore, in additionto being active, either or both of the first and second active materials2810 and 2815 may be photoactive. In other embodiments (not shown inFIG. 5), the second active material may comprise a solid electrolyte. Inaddition, in embodiments where either of the first and second activematerial 2810 and 2815 comprise a solid electrolyte, the PV device maylack an effective amount of liquid electrolyte. Although shown andreferred to in FIG. 5 as being p-type, a solid state layer (e.g., firstactive material comprising solid electrolyte) may in some embodimentsinstead be n-type semiconducting. In such embodiments, then, the secondactive material (e.g., TiO₂ (or other mesoporous material) as shown inFIG. 5) coated with a dye may be p-type semiconducting (as opposed tothe n-type semiconducting shown in, and discussed with respect to, FIG.5).

Substrate layers 2801 and 2825 (both shown in FIG. 5 as glass) form therespective external top and bottom layers of the example cell of FIG. 5.These layers may comprise any material of sufficient transparency topermit solar radiation to pass through to the active/photoactive layercomprising dye, first and second active and/or photoactive material 2810and 2815, such as glass, polymer, polyolefin, polyethylene,polypropylene, PEN, PET, PMMA, polycarbonate, Kapton, quartz, sapphire,aluminum, aluminum foil, silver foil, gold foil, metal foil, wood,concrete, and steel. Furthermore, in the embodiment shown in FIG. 5,electrode 2805 (shown as Pt/FTO) is the cathode, and electrode 2820 isthe anode. As with the example solar cell depicted in FIG. 4, solarradiation passes through substrate layer 2825 and electrode 2820 intothe active layer, whereupon at least a portion of the solar radiation isabsorbed so as to produce one or more excitons to enable electricalgeneration.

A solid state DSSC according to some embodiments may be constructed in asubstantially similar manner to that described above with respect to theDSSC depicted as stylized in FIG. 1. In the embodiment shown in FIG. 5,p-type active material 2810 corresponds to electrolyte 1503 of FIG. 1;n-type active material 2815 corresponds to both dye 1504 and ML 1505 ofFIG. 1; electrodes 2805 and 2820 respectively correspond to electrodelayers 1502 and 1506 of FIG. 1; and substrate layers 2801 and 2825respectively correspond to substrate layers 1501 and 1507.

Various embodiments of the present disclosure provide improved materialsand/or designs in various aspects of solar cell and other devices,including among other things, active materials (including hole-transportand/or electron-transport layers), interfacial layers, and overalldevice design.

Interfacial Layers

The present disclosure, in some embodiments, provides advantageousmaterials and designs of one or more interfacial layers within a PV,including thin-coat IFLs. Thin-coat IFLs may be employed in one or moreIFLs of a PV according to various embodiments discussed herein.

According to various embodiments, devices may optionally include aninterfacial layer between any two other layers and/or materials,although devices need not contain any interfacial layers. For example, aperovskite material device may contain zero, one, two, three, four,five, or more interfacial layers (such as the example device of FIG. 9,which contains five interfacial layers 3903, 3905, 3907, 3909, and3911). An interfacial layer may include any suitable material forenhancing charge transport and/or collection between two layers ormaterials; it may also help prevent or reduce the likelihood of chargerecombination once a charge has been transported away from one of thematerials adjacent to the interfacial layer. An interfacial layer mayadditionally physically and electrically homogenize its substrates tocreate variations in substrate roughness, dielectric constant, adhesion,creation or quenching of defects (e.g., charge traps, surface states).Suitable interfacial materials may include any one or more of: Ag; Al;Au; B; Bi; Ca; Cd; Ce; Co; Cu; Fe; Ga; Ge; H; In; Mg; Mn; Mo; Nb; Ni;Pt; Sb; Sc; Si; Sn; Ta; Ti; V; W; Y; Zn; Zr; carbides of any of theforegoing metals (e.g., SiC, Fe₃C, WC); silicides of any of theforegoing metals (e.g., Mg₂Si, SrSi₂, Sn₂Si); oxides of any of theforegoing metals (e.g., alumina, silica, titania, SnO₂, ZnO); sulfidesof any of the foregoing metals (e.g., CdS, MoS₂, SnS₂); nitrides of anyof the foregoing metals (e.g., Mg₃N₂, TiN, BN, Si₃N₄); selenides of anyof the foregoing metals (e.g., CdSe, FeS₂, ZnSe); tellurides of any ofthe foregoing metals (e.g., CdTe, TiTe₂, ZnTe); phosphides of any of theforegoing metals (e.g., InP, GaP); arsenides of any of the foregoingmetals (e.g., CoAs₃, GaAs, InGaAs, NiAs); antimonides of any of theforegoing metals (e.g., AlSb, GaSb, InSb); halides of any of theforegoing metals (e.g., CuCl, CuI, BiI₃); pseudohalides of any of theforegoing metals (e.g., CuSCN, AuCN); carbonates of any of the foregoingmetals (e.g., CaCO₃, Ce₂(CO₃)₃); functionalized or non-functionalizedalkyl silyl groups; graphite; graphene; fullerenes; carbon nanotubes;any mesoporous material and/or interfacial material discussed elsewhereherein; and combinations thereof (including, in some embodiments,bilayers, trilayers, or multi-layers of combined materials). In someembodiments, an interfacial layer may include perovskite material.Further, interfacial layers may comprise doped embodiments of anyinterfacial material mentioned herein (e.g., Y-doped ZnO, N-dopedsingle-wall carbon nanotubes). Interfacial layers may also comprise acompound having three of the above materials (e.g., CuTiO₃, Zn₂SnO₄) ora compound having four of the above materials (e.g., CoNiZnO).

First, as previously noted, one or more IFLs (e.g., either or both IFLs2626 and 2627 as shown in FIG. 4) may comprise a photoactive organiccompound of the present disclosure as a self-assembled monolayer (SAM)or as a thin film. When a photoactive organic compound of the presentdisclosure is applied as a SAM, it may comprise a binding group throughwhich it may be covalently or otherwise bound to the surface of eitheror both of the anode and cathode. The binding group of some embodimentsmay comprise any one or more of COOH, SiX₃ (where X may be any moietysuitable for forming a ternary silicon compound, such as Si(OR)₃ andSiCl₃), SO₃, PO₄H, OH, CH₂X (where X may comprise a Group 17 halide),and O. The binding group may be covalently or otherwise bound to anelectron-withdrawing moiety, an electron donor moiety, and/or a coremoiety. The binding group may attach to the electrode surface in amanner so as to form a directional, organized layer of a single molecule(or, in some embodiments, multiple molecules) in thickness (e.g., wheremultiple photoactive organic compounds are bound to the anode and/orcathode). As noted, the SAM may attach via covalent interactions, but insome embodiments it may attach via ionic, hydrogen-bonding, and/ordispersion force (i,e., Van Der Waals) interactions. Furthermore, incertain embodiments, upon light exposure, the SAM may enter into azwitterionic excited state, thereby creating a highly-polarized IFL,which may direct charge carriers from an active layer into an electrode(e.g., either the anode or cathode). This enhanced charge-carrierinjection may, in some embodiments, be accomplished by electronicallypoling the cross-section of the active layer and therefore increasingcharge-carrier drift velocities towards their respective electrode(e.g., hole to anode; electrons to cathode). Molecules for anodeapplications of some embodiments may comprise tunable compounds thatinclude a primary electron donor moiety bound to a core moiety, which inturn is bound to an electron-withdrawing moiety, which in turn is boundto a binding group. In cathode applications according to someembodiments, IFL molecules may comprise a tunable compound comprising anelectron poor moiety bound to a core moiety, which in turn is bound toan electron donor moiety, which in turn is bound to a binding group.When a photoactive organic compound is employed as an IFL according tosuch embodiments, it may retain photoactive character, although in someembodiments it need not be photoactive.

In addition or instead of a photoactive organic compound SAM IFL, a PVaccording to some embodiments may include a thin interfacial layer (a“thin-coat interfacial layer” or “thin-coat IFL”) coated onto at least aportion of either the first or the second active material of suchembodiments (e.g., first or second active material 2810 or 2815 as shownin FIG. 5). And, in turn, at least a portion of the thin-coat IFL may becoated with a dye. The thin-coat IFL may be either n- or p-type; in someembodiments, it may be of the same type as the underlying material(e.g., TiO₂ or other mesoporous material, such as TiO₂ of second activematerial 2815). The second active material may comprise TiO₂ coated witha thin-coat IFL comprising alumina (e.g., Al₂O₃) (not shown in FIG. 5),which in turn is coated with a dye. References herein to TiO₂ and/ortitania are not intended to limit the ratios of titanium and oxide insuch titanium-oxide compounds described herein. That is, a titaniacompound may comprise titanium in any one or more of its variousoxidation states (e.g., titanium I, titanium II, titanium III, titaniumIV), and thus various embodiments may include stoichiometric and/ornon-stoichiometric amounts of titanium and oxide. Thus, variousembodiments may include (instead or in addition to TiO₂) Ti_(x)O_(y),where x may be any value, integer or non-integer, between 1 and 100. Insome embodiments, x may be between approximately 0.5 and 3. Likewise, ymay be between approximately 1.5 and 4 (and, again, need not be aninteger). Thus, some embodiments may include, e.g., TiO₂ and/or Ti₂O₃.In addition, titania in whatever ratios or combination of ratios betweentitanium and oxide may be of any one or more crystal structures in someembodiments, including any one or more of anatase, rutile, andamorphous.

Other example metal oxides for use in the thin-coat IFL of someembodiments may include semiconducting metal oxides, such as NiO, WO₃,V₂O₅, or MoO₃. The embodiment wherein the second (e.g., n-type) activematerial comprises TiO₂ coated with a thin-coat IFL comprising Al₂O₃could be formed, for example, with a precursor material such asAl(NO₃)₃.xH₂O, or any other material suitable for depositing Al₂O₃ ontothe TiO₂, followed by thermal annealing and dye coating. In exampleembodiments wherein a MoO₃ coating is instead used, the coating may beformed with a precursor material such as Na₂Mo₄.2H₂O; whereas a V₂O₅coating according to some embodiments may be formed with a precursormaterial such as NaVO₃; and a WO₃ coating according to some embodimentsmay be formed with a precursor material such as NaWO₄.H₂O. Theconcentration of precursor material (e.g., Al(NO₃)₃.xH₂O) may affect thefinal film thickness (here, of Al₂O₃) deposited on the TiO₂ or otheractive material. Thus, modifying the concentration of precursor materialmay be a method by which the final film thickness may be controlled. Forexample, greater film thickness may result from greater precursormaterial concentration. Greater film thickness may not necessarilyresult in greater PCE in a PV device comprising a metal oxide coating.Thus, a method of some embodiments may include coating a TiO₂ (or othermesoporous) layer using a precursor material having a concentration inthe range of approximately 0.5 to 10.0 mM; other embodiments may includecoating the layer with a precursor material having a concentration inthe range of approximately 2.0 to 6.0 mM; or, in other embodiments,approximately 2.5 to 5.5 mM.

Furthermore, although referred to herein as Al₂O₃ and/or alumina, itshould be noted that various ratios of aluminum and oxygen may be usedin forming alumina. Thus, although some embodiments discussed herein aredescribed with reference to Al₂O₃, such description is not intended todefine a required ratio of aluminum in oxygen. Rather, embodiments mayinclude any one or more aluminum-oxide compounds, each having analuminum oxide ratio according to Al_(x)O_(y), where x may be any value,integer or non-integer, between approximately 1 and 100. In someembodiments, x may be between approximately 1 and 3 (and, again, neednot be an integer). Likewise, y may be any value, integer ornon-integer, between 0.1 and 100. In some embodiments, y may be between2 and 4 (and, again, need not be an integer). In addition, variouscrystalline forms of Al_(x)O_(y) may be present in various embodiments,such as alpha, gamma, and/or amorphous forms of alumina.

Likewise, although referred to herein as MoO₃, WO₃, and V₂O₅, suchcompounds may instead or in addition be represented as Mo_(x)O_(y),W_(x)O_(y), and V_(x)O_(y), respectively. Regarding each of Mo_(x)O_(y)and W_(x)O_(y), x may be any value, integer or non-integer, betweenapproximately 0.5 and 100; in some embodiments, it may be betweenapproximately 0.5 and 1.5. Likewise, y may be any value, integer ornon-integer, between approximately 1 and 100. In some embodiments, y maybe any value between approximately 1 and 4. Regarding V_(x)O_(y), x maybe any value, integer or non-integer, between approximately 0.5 and 100;in some embodiments, it may be between approximately 0.5 and 1.5.Likewise, y may be any value, integer or non-integer, betweenapproximately 1 and 100; in certain embodiments, it may be an integer ornon-integer value between approximately 1 and 10.

Similarly, references in some illustrative embodiments herein to CsSnI₃are not intended to limit the ratios of component elements in thecesium-tin-iodine compounds according to various embodiments. Someembodiments may include stoichiometric and/or non-stoichiometric amountsof tin and iodide, and thus such embodiments may instead or in additioninclude various ratios of cesium, tin, and iodine, such as any one ormore cesium-tin-iodine compounds, each having a ratio ofCs_(x)Sn_(y)I_(z). In such embodiments, x may be any value, integer ornon-integer, between 0.1 and 100. In some embodiments, x may be betweenapproximately 0.5 and 1.5 (and, again, need not be an integer).Likewise, y may be any value, integer or non-integer, between 0.1 and100. In some embodiments, y may be between approximately 0.5 and 1.5(and, again, need not be an integer). Likewise, z may be any value,integer or non-integer, between 0.1 and 100. In some embodiments, z maybe between approximately 2.5 and 3.5. Additionally CsSnI₃ may be dopedor compounded with other materials, such as SnF₂, in ratios ofCsSnI₃:SnF₂ ranging from 0.1:1 to 100:1, including all values (integerand non-integer) in between.

In addition, a thin-coat IFL may comprise a bilayer. Thus, returning tothe example wherein the thin-coat IFL comprises a metal-oxide (such asalumina), the thin-coat IFL may comprise TiO₂-plus-metal-oxide. Such athin-coat IFL may have a greater ability to resist charge recombinationas compared to mesoporous TiO₂ or other active material alone.Furthermore, in forming a TiO₂ layer, a secondary TiO₂ coating is oftennecessary in order to provide sufficient physical interconnection ofTiO₂ particles, according to some embodiments of the present disclosure.Coating a bilayer thin-coat IFL onto mesoporous TiO₂ (or othermesoporous active material) may comprise a combination of coating usinga compound comprising both metal oxide and TiCl₄, resulting in anbilayer thin-coat IFL comprising a combination of metal-oxide andsecondary TiO₂ coating, which may provide performance improvements overuse of either material on its own.

In some embodiments, the IFL may comprise a titanate. A titanateaccording to some embodiments may be of the general formula M′TiO₃,where: M′ comprises any 2+ cation. In some embodiments, M′ may comprisea cationic form of Be, Mg, Ca, Sr, Ba, Ni, Zn, Cd, Hg, Cu, Pd, Pt, Sn,or Pb. In some embodiments, the IFL may comprise a single species oftitanate, which in other embodiments, the IFL may comprise two or moredifferent species of titanates. In one embodiment, the titanate has theformula SrTiO₃. In another embodiment, the titanate may have the formulaBaTiO₃. In yet another embodiment, the titanate may have the formulaCaTiO₃.

By way of explanation, and without implying any limitation, titanateshave a perovskite crystalline structure and strongly seed the perovskitematerial (e.g., MAPbI₃, FAPbI₃) growth conversion process. Titanatesgenerally also meet other IFL requirements, such as ferroelectricbehavior, sufficient charge carrier mobility, optical transparency,matched energy levels, and high dielectric constant.

In other embodiments, the IFL may comprise a zirconate. A zirconateaccording to some embodiments may be of the general formula M′ZrO₃,where: M′ comprises any 2+ cation. In some embodiments, M′ may comprisea cationic form of Be, Mg, Ca, Sr, Ba, Ni, Zn, Cd, Hg, Cu, Pd, Pt, Sn,or Pb. In some embodiments, the IFL may comprise a single species ofzirconate, which in other embodiments, the IFL may comprise two or moredifferent species of zirconate. In one embodiment, the zirconate has theformula SrZrO₃. In another embodiment, the zirconate may have theformula BaZrO₃. In yet another embodiment, the zirconate may have theformula CaZrO₃.

By way of explanation, and without implying any limitation, zirconatehave a perovskite crystalline structure and strongly seed the perovskitematerial (e.g., MAPbI₃, FAPbI₃) growth conversion process. Zirconatesgenerally also meet other IFL requirements, such as ferroelectricbehavior, sufficient charge carrier mobility, optical transparency,matched energy levels, and high dielectric constant.

Further, in other embodiments, an IFL may comprise a combination of azirconate and a titanate in the general formula M′[Zr_(x)Ti_(1-x)]O₃,where X is greater than 0 but less than one 1, and M′ comprises any 2+cation. In some embodiments, M′ may comprise a cationic form of Be, Mg,Ca, Sr, Ba, Ni, Zn, Cd, Hg, Cu, Pd, Pt, Sn, or Pb. In some embodiments,the IFL may comprise a single species of zirconate, which in otherembodiments, the IFL may comprise two or more different species ofzirconate. In one embodiment, the zirconate/titanate combination has theformula Pb[Zr_(x)Ti_(1-x)]O₃. In another embodiment, thezirconate/titanate combination has the formula Pb[Zr_(0.52)Ti_(0.48)]O₃.

By way of explanation, and without implying any limitation, azirconate/titanate combination have a perovskite crystalline structureand strongly seed the perovskite material (e.g., MAPbI₃, FAPbI₃) growthconversion process. Zirconate/titanate combinations generally also meetother IFL requirements, such as ferroelectric behavior, sufficientcharge carrier mobility, optical transparency, matched energy levels,and high dielectric constant.

In other embodiments, the IFL may comprise a niobate. A niobateaccording to some embodiments may be of the general formula M′NiO₃,where: M′ comprises any 1+ cation. In some embodiments, M′ may comprisea cationic form of Li, Na, K, Rb, Cs, Cu, Ag, Au, Tl, ammonium, or H. Insome embodiments, the IFL may comprise a single species of niobate,which in other embodiments, the IFL may comprise two or more differentspecies of niobate. In one embodiment, the niobate has the formulaLiNbO₃. In another embodiment, the niobate may have the formula NaNbO₃.In yet another embodiment, the niobate may have the formula AgNbO₃.

By way of explanation, and without implying any limitation, niobatesgenerally meet IFL requirements, such as piezoelectric behavior,non-linear optical polarizability, photoelasticity, ferroelectricbehavior, Pockels effect, sufficient charge carrier mobility, opticaltransparency, matched energy levels, and high dielectric constant.

In one embodiment, a perovskite material device may be formulated bycasting PbI₂ onto a SrTiO₃-coated ITO substrate. The PbI₂ may beconverted to MAPbI₃ by a dipping process. This process is described ingreater detail below. This resulting conversion of PbI₂ to MAPbI₃ ismore complete (as observed by optical spectroscopy) as compared to thepreparation of the substrate without SrTiO₃.

Any interfacial material discussed herein may further comprise dopedcompositions. To modify the characteristics (e.g., electrical, optical,mechanical) of an interfacial material, a stoichiometric ornon-stoichiometric material may be doped with one or more elements(e.g., Na, Y, Mg, N, P) in amounts ranging from as little as 1 ppb to 50mol %. Some examples of interfacial materials include: NiO, TiO₂,SrTiO₃, Al₂O₃, ZrO₂, WO₃, V₂O₅, MO₃, ZnO, graphene, and carbon black.Examples of possible dopants for these interfacial materials include:Li, Na, Be, Mg, Ca, Sr, Ba, Sc, Y, Nb, Ti, Fe, Co, Ni, Cu, Ga, Sn, In,B, N, P, C, S, As, a halide, a pseudohalide (e.g., cyanide, cyanate,isocyanate, fulminate, thiocyanate, isothiocyanate, azide,tetracarbonylcobaltate, carbamoyldicyanomethanide,dicyanonitrosomethanide, dicyanamide, and tricyanomethanide), and Al inany of its oxidation states. References herein to doped interfacialmaterials are not intended to limit the ratios of component elements ininterfacial material compounds.

The thin-coat IFLs and methods of coating them onto TiO₂ previouslydiscussed may, in some embodiments, be employed in DSSCs comprisingliquid electrolytes. Thus, returning to the example of a thin-coat IFLand referring back to FIG. 1 for an example, the DSSC of FIG. 1 couldfurther comprise a thin-coat IFL as described above coated onto themesoporous layer 1505 (that is, the thin-coat IFL would be insertedbetween mesoporous layer 1505 and dye 1504).

In some embodiments, the thin-coat IFLs previously discussed in thecontext of DSSCs may be used in any interfacial layer of a semiconductordevice such as a PV (e.g., a hybrid PV or other PV), field-effecttransistor, light-emitting diode, non-linear optical device, memristor,capacitor, rectifier, rectifying antenna, etc. Furthermore, thin-coatIFLs of some embodiments may be employed in any of various devices incombination with other compounds discussed in the present disclosure,including but not limited to any one or more of the following of variousembodiments of the present disclosure: solid hole-transport materialsuch as active material and additives (such as, in some embodiments,chenodeoxycholic acid or 1,8-diiodooctane).

In some embodiments, multiple IFLs made from different materials may bearranged adjacent to each other to form a composite IFL. Thisconfiguration may involve two different IFLs, three different IFLs, oran even greater number of different IFLs. The resulting multi-layer IFLor composite IFL may be used in lieu of a single-material IFL. Forexample, a composite IFL may be used as IFL 2626 and/or as IFL 2627 incell 2610, shown in the example of FIG. 4. While the composite IFLdiffers from a single-material IFL, the assembly of a perovskitematerial PV cell having multi-layer IFLs is not substantially differentthan the assembly of a perovskite material PV cell having onlysingle-material IFLs.

Generally, the composite IFL may be made using any of the materialsdiscussed herein as suitable for an IFL. In one embodiment, the IFLcomprises a layer of Al₂O₃ and a layer of ZnO or M:ZnO (doped ZnO, e.g.,Be:ZnO, Mg:ZnO, Ca:ZnO, Sr:ZnO, Ba:ZnO, Sc:ZnO, Y:ZnO, Nb:ZnO). In anembodiment, the IFL comprises a layer of ZrO₂ and a layer of ZnO orM:ZnO. In certain embodiments, the IFL comprises multiple layers. Insome embodiments, a multi-layer IFL generally has a conductor layer, adielectric layer, and a semi-conductor layer. In particular embodimentsthe layers may repeat, for example, a conductor layer, a dielectriclayer, a semi-conductor layer, a dielectric layer, and a semi-conductorlayer. Examples of multi-layer IFLs include an IFL having an ITO layer,an Al₂O₃ layer, a ZnO layer, and a second Al₂O₃ layer; an IFL having anITO layer, an Al₂O₃ layer, a ZnO layer, a second Al₂O₃ layer, and asecond ZnO layer; an IFL having an ITO layer, an Al₂O₃ layer, a ZnOlayer, a second Al₂O₃ layer, a second ZnO layer, and a third Al₂O₃layer; and IFLs having as many layers as necessary to achieve thedesired performance characteristics. As discussed previously, referencesto certain stoichiometric ratios are not intended to limit the ratios ofcomponent elements in IFL layers according to various embodiments.

Arranging two or more adjacent IFLs as a composite IFL may outperform asingle IFL in perovskite material PV cells where attributes from eachIFL material may be leveraged in a single IFL. For example, in thearchitecture having an ITO layer, an Al₂O₃ layer, and a ZnO layer, whereITO is a conducting electrode, Al₂O₃ is a dielectric material and ZnO isa n-type semiconductor, ZnO acts as an electron acceptor with wellperforming electron transport properties (e.g., mobility). Additionally,Al₂O₃ is a physically robust material that adheres well to ITO,homogenizes the surface by capping surface defects (e.g., charge traps),and improves device diode characteristics through suppression of darkcurrent.

Perovskite Material

A perovskite material may be incorporated into one or more aspects of aPV or other device. A perovskite material according to some embodimentsmay be of the general formula C_(w)M_(y)X_(z), where: C comprises one ormore cations (e.g., an amine, ammonium, a Group 1 metal, a Group 2metal, and/or other cations or cation-like compounds); M comprises oneor more metals (examples including Fe, Co, Ni, Cu, Ag, Au, Tl, In, Sb,Sn, Pb, Bi, Ga, Ge, Ti, and Zn); X comprises one or more anions; and w,y, and z represent real numbers between 1 and 20. In some embodiments, Cmay include one or more organic cations. In some embodiments, eachorganic cation C may be larger than each metal M, and each anion X maybe capable of bonding with both a cation C and a metal M. In particularembodiments, a perovskite material may be of the formula CMX₃.

In certain embodiments, C may include an ammonium, an organic cation ofthe general formula [NR₄]⁺ where the R groups may be the same ordifferent groups. Suitable R groups include, but are not limited to:methyl, ethyl, propyl, butyl, pentyl group or isomer thereof; anyalkane, alkene, or alkyne CxHy, where x=1-20, y=1-42, cyclic, branchedor straight-chain; alkyl halides, CxHyXz, x=1-20, y=0-42, z=1-42, X=F,Cl, Br, or I; any aromatic group (e.g., phenyl, alkylphenyl,alkoxyphenyl, pyridine, naphthalene); cyclic complexes where at leastone nitrogen is contained within the ring (e.g., pyridine, pyrrole,pyrrolidine, piperidine, tetrahydroquinoline); any sulfur-containinggroup (e.g., sulfoxide, thiol, alkyl sulfide); any nitrogen-containinggroup (nitroxide, amine); any phosphorous containing group (phosphate);any boron-containing group (e.g., boronic acid); any organic acid (e.g.,acetic acid, propanoic acid); and ester or amide derivatives thereof;any amino acid (e.g., glycine, cysteine, proline, glutamic acid,arginine, serine, histindine, 5-ammoniumvaleric acid) including alpha,beta, gamma, and greater derivatives; any silicon containing group(e.g., siloxane); and any alkoxy or group, —OCxHy, where x=0-20, y=1-42.

In certain embodiments, C may include a formamidinium, an organic cationof the general formula [R₂NCRNR₂]⁺ where the R groups may be the same ordifferent groups. Suitable R groups include, but are not limited to:hydrogen, methyl, ethyl, propyl, butyl, pentyl group or isomer thereof;any alkane, alkene, or alkyne CxHy, where x=1-20, y=1-42, cyclic,branched or straight-chain; alkyl halides, CxHyXz, x=1-20, y=0-42,z=1-42, X=F, Cl, Br, or I; any aromatic group (e.g., phenyl, alkylphenl,alkoxyphenyl, pyridine, naphthalene); cyclic complexes where at leastone nitrogen is contained within the ring (e.g., imidazole,benzimidazole, dihydropyrimidine, (azolidinylidenemethyl)pyrrolidine,triazole); any sulfur-containing group (e.g., sulfoxide, thiol, alkylsulfide); any nitrogen-containing group (nitroxide, amine); anyphosphorous containing group (phosphate); any boron-containing group(e.g., boronic acid); any organic acid (acetic acid, propanoic acid) andester or amide derivatives thereof; any amino acid (e.g., glycine,cysteine, proline, glutamic acid, arginine, serine, histindine,5-ammoniumvaleric acid) including alpha, beta, gamma, and greaterderivatives; any silicon containing group (e.g., siloxane); and anyalkoxy or group, —OCxHy, where x=0-20, y=1-42.

Formula 1 illustrates the structure of a formamidinium cation having thegeneral formula of [R₂NCRNR₂]⁺ as described above. Formula 2 illustratesexamples structures of several formamidinium cations that may serve as acation “C” in a perovskite material.

In certain embodiments, C may include a guanidinium, an organic cationof the general formula [(R₂N)₂C═NR₂]⁺ where the R groups may be the sameor different groups. Suitable R groups include, but are not limited to:hydrogen, methyl, ethyl, propyl, butyl, pentyl group or isomer thereof;any alkane, alkene, or alkyne CxHy, where x=1-20, y=1-42, cyclic,branched or straight-chain; alkyl halides, CxHyXz, x=1-20, y=0-42,z=1-42, X=F, Cl, Br, or I; any aromatic group (e.g., phenyl, alkylphenl,alkoxyphenyl, pyridine, naphthalene); cyclic complexes where at leastone nitrogen is contained within the ring (e.g.,octahydropyrimido[1,2-a]pyrimidine, pyrimido[1,2-a]pyrimidine,hexahydroimidazo[1,2-a]imidazole, hexahydropyrimidin-2-imine); anysulfur-containing group (e.g., sulfoxide, thiol, alkyl sulfide); anynitrogen-containing group (nitroxide, amine); any phosphorous containinggroup (phosphate); any boron-containing group (e.g., boronic acid); anyorganic acid (acetic acid, propanoic acid) and ester or amidederivatives thereof; any amino acid (e.g., glycine, cysteine, proline,glutamic acid, arginine, serine, histindine, 5-ammoniumvaleric acid)including alpha, beta, gamma, and greater derivatives; any siliconcontaining group (e.g., siloxane); and any alkoxy or group, —OCxHy,where x=0-20, y=1-42.

Formula 3 illustrates the structure of a guanidinium cation having thegeneral formula of [(R₂N)₂C═NR₂]⁺ as described above. Formula 4illustrates examples of structures of several guanidinium cations thatmay serve as a cation “C” in a perovskite material.

In certain embodiments, C may include an ethene tetramine cation, anorganic cation of the general formula [(R₂N)₂C═C(NR₂)₂]⁺ where the Rgroups may be the same or different groups. Suitable R groups include,but are not limited to: hydrogen, methyl, ethyl, propyl, butyl, pentylgroup or isomer thereof; any alkane, alkene, or alkyne CxHy, wherex=1-20, y=1-42, cyclic, branched or straight-chain; alkyl halides,CxHyXz, x=1-20, y=0-42, z=1-42, X=F, Cl, Br, or I; any aromatic group(e.g., phenyl, alkylphenl, alkoxyphenyl, pyridine, naphthalene); cycliccomplexes where at least one nitrogen is contained within the ring(e.g., 2-hexahydropyrimidin-2-ylidenehexahydropyrimidine,octahydropyrazino[2,3-b]pyrazine, pyrazino[2,3-b]pyrazine,quinoxalino[2,3-b]quinoxaline); any sulfur-containing group (e.g.,sulfoxide, thiol, alkyl sulfide); any nitrogen-containing group(nitroxide, amine); any phosphorous containing group (phosphate); anyboron-containing group (e.g., boronic acid); any organic acid (aceticacid, propanoic acid) and ester or amide derivatives thereof; any aminoacid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine,histindine, 5-ammoniumvaleric acid) including alpha, beta, gamma, andgreater derivatives; any silicon containing group (e.g., siloxane); andany alkoxy or group, —OCxHy, where x=0-20, y=1-42.

Formula 5 illustrates the structure of an ethene tetramine cation havingthe general formula of [(R₂N)₂C═C(NR₂)₂]⁺ as described above. Formula 6illustrates examples of structures of several ethene tetramine ions thatmay serve as a cation “C” in a perovskite material.

In certain embodiments, C may include an imidazolium cation, anaromatic, cyclic organic cation of the general formula [CRNRCRNRCR]⁺where the R groups may be the same or different groups. Suitable Rgroups may include, but are not limited to: hydrogen, methyl, ethyl,propyl, butyl, pentyl group or isomer thereof; any alkane, alkene, oralkyne CxHy, where x=1-20, y=1-42, cyclic, branched or straight-chain;alkyl halides, CxHyXz, x=1-20, y=0-42, z=1-42, X=F, Cl, Br, or I; anyaromatic group (e.g., phenyl, alkylphenl, alkoxyphenyl, pyridine,naphthalene); cyclic complexes where at least one nitrogen is containedwithin the ring (e.g.,2-hexahydropyrimidin-2-ylidenehexahydropyrimidine,octahydropyrazino[2,3-b]pyrazine, pyrazino[2,3-b]pyrazine,quinoxalino[2,3-b]quinoxaline); any sulfur-containing group (e.g.,sulfoxide, thiol, alkyl sulfide); any nitrogen-containing group(nitroxide, amine); any phosphorous containing group (phosphate); anyboron-containing group (e.g., boronic acid); any organic acid (aceticacid, propanoic acid) and ester or amide derivatives thereof; any aminoacid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine,histindine, 5-ammoniumvaleric acid) including alpha, beta, gamma, andgreater derivatives; any silicon containing group (e.g., siloxane); andany alkoxy or group, —OCxHy, where x=0-20, y=1-42.

In some embodiments, X may include one or more halides. In certainembodiments, X may instead or in addition include a Group 16 anion. Incertain embodiments, the Group 16 anion may be oxide, sulfide, selenide,or telluride. In certain embodiments, X may instead or in additioninclude one or more a pseudohalides (e.g., cyanide, cyanate, isocyanate,fulminate, thiocyanate, isothiocyanate, azide, tetracarbonylcobaltate,carbamoyldicyanomethanide, dicyanonitrosomethanide, dicyanamide, andtricyanomethanide).

In one embodiment, a perovskite material may comprise the empiricalformula CMX₃ where: C comprises one or more of the aforementionedcations, a Group 1 metal, a Group 2 metal, and/or other cations orcation-like compounds; M comprises one or more metals (examplesincluding Fe, Co, Ni, Cu, Ag, Au, Sb, Sn, Pb, Bi, Ga, Ge, Ti, Tl, andZn); and X comprises one or more of the aforementioned anions.

In one embodiment, a perovskite material may comprise the empiricalformula C₃M₂X₉ where: C comprises one or more of the aforementionedcations, a Group 1 metal, a Group 2 metal, and/or other cations orcation-like compounds; M comprises one or more metals (examplesincluding Fe, Co, Ni, Cu, Ag, Au, Sb, Sn, Pb, Bi, Ga, Ge, Ti, Tl, andZn); and X comprises one or more of the aforementioned anions.

In one embodiment, a perovskite material may comprise the empiricalformula CM₂X₇ where: C comprises one or more of the aforementionedcations, a Group 1 metal, a Group 2 metal, and/or other cations orcation-like compounds; M comprises one or more metals (examplesincluding Fe, Co, Ni, Cu, Ag, Au, Sb, Sn, Pb, Bi, Ga, Ge, Ti, Tl, andZn); and X comprises one or more of the aforementioned anions.

In one embodiment, a perovskite material may comprise the empiricalformula C₂MX₄ where: C comprises one or more of the aforementionedcations, a Group 1 metal, a Group 2 metal, and/or other cations orcation-like compounds; M comprises one or more metals (examplesincluding Fe, Co, Ni, Cu, Ag, Au, Sb, Sn, Pb, Bi, Ga, Ge, Ti, Tl, andZn); and X comprises one or more of the aforementioned anions.

Perovskite materials may also comprise mixed ion formulations where C,M, or X comprise two or more species, for example, Cs_(0.1)FA_(0.9)PbI₃;FAPb_(0.5)Sn_(0.5)I₃; FA_(0.83)Cs_(0.17)Pb(I_(0.6)Br_(0.4))₃;FA_(0.83)Cs_(0.12)Rb_(0.05)Pb(I_(0.6)Br_(0.4))₃ andFA_(0.85)MA_(0.15)Pb(I_(0.85)Br_(0.15))₃.

Examples of perovskite materials according to various embodimentsinclude CsSnI₃ (previously discussed herein) and Cs_(x)Sn_(y)I_(z) (withx, y, and z varying in accordance with the previous discussion). Otherexamples include compounds of the general formula CsSnX₃, where X may beany one or more of: I₃, I_(2.95)F_(0.05); I₂Cl; ICl₂; and Cl₃. In otherembodiments, X may comprise any one or more of I, Cl, F, and Br inamounts such that the total ratio of X as compared to Cs and Sn resultsin the general stoichiometry of CsSnX₃. In some embodiments, thecombined stoichiometry of the elements that constitute X may follow thesame rules as I_(z) as previously discussed with respect toCs_(x)Sn_(y)I_(z). Yet other examples include compounds of the generalformula RNH₃PbX₃, where R may be C—H_(2n+1), with n ranging from 0-10,and X may include any one or more of F, Cl, Br, and I in amounts suchthat the total ratio of X as compared to the cation RNH₃ and metal Pbresults in the general stoichiometry of RNH₃PbX₃. Further, some specificexamples of R include H, alkyl chains (e.g., CH₃, CH₃CH₂, CH₃CH₂CH₂, andso on), and amino acids (e.g., glycine, cysteine, proline, glutamicacid, arginine, serine, histindine, 5-ammoniumvaleric acid) includingalpha, beta, gamma, and greater derivatives.

Other Exemplar Electronic Devices

Another example device according to some embodiments is a monolithicthin-film PV and battery device, or hybrid PV battery.

A hybrid PV battery according to some embodiments of the presentdisclosure may generally include a PV cell and a battery portion sharinga common electrode and electrically coupled in series or parallel. Forexample, hybrid PV batteries of some embodiments may be described byreference to FIG. 6, which is a stylized diagram of components of anexemplar hybrid PV battery, and includes: an encapsulant 3601; at leastthree electrodes 3602, 3604, and 3606, at least one of which is a commonelectrode (here 3604) shared by the PV portion of the device and thebattery portion of the device; a PV active layer 3603; a battery activelayer 3605; and a substrate 3607. In such example embodiments, the PVcell of the device may comprise one electrode 3602 (which may in someembodiments be referred to as a PV electrode) and the PV active layer3603, while the battery of the device may comprise the other non-sharedelectrode 3606 (which may in some embodiments be referred to as abattery electrode) and the battery active layer 3605. The PV cell andthe battery portion of such embodiments share the common electrode 3604.In some embodiments, the hybrid PV battery may be monolithic, that is,imprinted on a single substrate. In such embodiments, both the PV celland the battery portion should be thin-film type devices. In someembodiments, both the PV cell and the battery may be capable of beingprinted by high-throughput techniques such as ink-jet, die-slot,gravure, and imprint roll-to-roll printing.

The PV cell of some embodiments may include a DSSC, a BHJ, a hybrid PV,or any other PV known in the art, such as cadmium telluride (CdTe) PVs,or CIGS (copper-indium-gallium-selenide) PVs. For example, inembodiments where the PV cell of a hybrid PV battery comprises a DSSC,the PV cell may be described by comparison between the exemplar liquidelectrolyte DSSC of FIG. 1 and the PV cell of the exemplar hybrid PVbattery of FIG. 6. Specifically, PV electrode 3602 may correspond toelectrode layer 1502; PV active layer 3603 may correspond to electrolyte1503, dye 1504, and ML 1505; and common electrode 3604 may correspond toelectrode layer 1506. Any other PV may similarly correspond to the PVcell components of some embodiments of a hybrid PV battery, as will beapparent to one of ordinary skill in the art with the benefit of thisdisclosure. Furthermore, as with the PV devices discussed herein, the PVactive layer within the PV cell of the device may in some embodimentscomprise any one or more of: an interfacial layer, and first and/orsecond active material (each of which may be n-type or p-typesemiconducting, and either or both of which may include a metal-oxideinterfacial layer according to various embodiments discussed herein).

The battery portion of such devices may be composed according tobatteries known in the art, such as lithium ion or zinc air. In someembodiments, the battery may be a thin-film battery.

Thus, for example, a hybrid PV battery according to some embodiments mayinclude a DSSC integrated with a zinc-air battery. Both devices arethin-film type and are capable of being printed by high-throughputtechniques such as ink-jet roll-to-roll printing, in accordance withsome embodiments of the present disclosure. In this example, thezinc-air battery is first printed on a substrate (corresponding tosubstrate 3607) completed with counter-electrode. The batterycounter-electrode then becomes the common electrode (corresponding tocommon electrode 3604) as the photoactive layer (corresponding to PVactive layer 3603) is subsequently printed on the electrode 3604. Thedevice is completed with a final electrode (corresponding to PVelectrode 3602), and encapsulated in an encapsulant (corresponding toencapsulant 3601). The encapsulant may comprise epoxy, polyvinylidenefluoride (PVDF), ethyl-vinyl acetate (EVA), Parylene C, or any othermaterial suitable for protecting the device from the environment.

In some embodiments, a hybrid PV battery may provide several advantagesover known batteries or PV devices. In embodiments in which the hybridPV battery is monolithic, it may exhibit increased durability due to thelack of connecting wires. The combination of two otherwise separatedevices into one (PV and battery) further may advantageously reduceoverall size and weight compared to use of a separate PV to charge aseparate battery. In embodiments in which the hybrid PV batterycomprises a thin-film type PV cell and battery portion, the thin-type PVcell may advantageously be capable of being printed in-line with abattery on substrates known to the battery industry, such as polyimides(e.g., Kapton or polyethylene terephthalate (PET)). In addition, thefinal form factor of such hybrid PV batteries may, in some embodiments,be made to fit form factors of standard batteries (e.g., for use inconsumer electronics, such as coin, AAA, AA, C, D, or otherwise; or foruse in, e.g., cellular telephones). In some embodiments, the batterycould be charged by removal from a device followed by placement insunlight. In other embodiments, the battery may be designed such thatthe PV cell of the battery is externally-facing from the device (e.g.,the battery is not enclosed in the device) so that the device may becharged by exposure to sunlight. For example, a cellular telephone maycomprise a hybrid PV battery with the PV cell of the battery facing theexterior of the phone (as opposed to placing the battery entirely withina covered portion of the phone).

In addition, some embodiments of the present disclosure may provide amulti-photoactive-layer PV cell. Such a cell may include at least twophotoactive layers, each photoactive layer separated from the other by ashared double-sided conductive (i.e., conductor/insulator/conductor)substrate. The photoactive layers and shared substrate(s) of someembodiments may be sandwiched between conducting layers (e.g.,conducting substrates, or conductors bound or otherwise coupled to asubstrate). In some embodiments, any one or more of the conductorsand/or substrates may be transparent to at least some electromagneticradiation within the UV, visible, or IR spectrum.

Each photoactive layer may have a makeup in accordance with the activeand/or photoactive layer(s) of any of the various PV devices discussedelsewhere herein (e.g., DSSC, BHJ, hybrid). In some embodiments, eachphotoactive layer may be capable of absorbing different wavelengths ofelectromagnetic radiation. Such configuration may be accomplished by anysuitable means which will be apparent to one of ordinary skill in theart with the benefit of this disclosure.

An exemplary multi-photoactive-layer PV cell according to someembodiments may be described by reference to the stylized diagram ofFIG. 7, which illustrates the basic structure of some such PV cells.FIG. 7 shows first and second photoactive layers (3701 and 3705,respectively) separated by a shared double-sided conductive substrate3710 (e.g., FIG. 7 shows an architecture of the general natureconductor/insulator/conductor). The two photoactive layers 3701 and3705, and the shared substrate 3710, are sandwiched between first andsecond conductive substrates 3715 and 3720. In this exemplary set-up,each photoactive layer 3701 and 3705 comprises a dye in accordance witha DSSC-like configuration. Further, the dye of the first photoactivelayer 3701 is capable of absorbing electromagnetic radiation at a firstportion of the visible EM spectrum (e.g., incident blue and green light3750 and 3751), while the dye of the second photoactive layer 3705 iscapable of absorbing electromagnetic radiation at a second, different,portion of the visible EM spectrum (e.g., red and yellow light 3755 and3756). It should be noted that, while not the case in the deviceillustrated in FIG. 7, devices according to some embodiments may includedyes (or other photoactive layer materials) capable of absorbingradiation in ranges of wavelengths that, while different, nonethelessoverlap. Upon excitation in each photoactive layer (e.g., by incidentsolar radiation), holes may flow from the first photoactive layer 3701to the first conductive substrate 3715, and likewise from the secondphotoactive layer 3705 to the second conductive substrate 3720.Concomitant electron transport may accordingly take place from eachphotoactive layer 3701 and 3705 to the shared conductive substrate 3710.An electrical conductor or conductors (e.g., lead 3735 as in FIG. 7) mayprovide further transport of holes away from each of the first andsecond conductive substrates 3715 and 3720 toward a negative direction3730 of the circuit (e.g., toward a cathode, negative battery terminal,etc.), while a conductor or conductors (e.g., leads 3745 and 3746 as inFIG. 7) may carry electrons away from the shared substrate 3710, towarda positive direction 3735 of the circuit.

In some embodiments, two or more multi-photoactive-layer PV cells may beconnected or otherwise electrically coupled (e.g., in series). Forexample, referring back to the exemplary embodiment of FIG. 7, the wire3735 conducting electrons away from each of the first and secondconductive substrates 3715 and 3720 may in turn be connected to adouble-sided shared conductive substrate of a secondmulti-photoactive-layer PV cell (e.g., a shared conductive substratecorresponding to shared conductive substrate 3710 of the exemplary PVcell of FIG. 7). Any number of PV cells may be so connected in series.The end effect in some embodiments is essentially multiple parallel PVcell pairs electrically coupled in series (wherein eachmulti-photoactive-layer PV cell with two photoactive layers and a shareddouble-sided conductive substrate could be considered a pair of parallelPV cells). Similarly, a multi-photoactive-layer PV cell with threephotoactive layers and two shared double-sided conductive substratessandwiched between each photoactive layer could equivalently beconsidered a trio of parallel PV cells, and so on formulti-photoactive-layer PV cells comprising four, five, and morephotoactive layers.

Furthermore, electrically coupled multi-photoactive-layer PV cells mayfurther be electrically coupled to one or more batteries to form ahybrid PV battery according to certain embodiments.

In certain embodiments, the electrical coupling of two or moremulti-photoactive-layer PV cells (e.g., series connection of two or moreunits of parallel PV cell pairs) in series may be carried out in a formsimilar to that illustrated in FIG. 8A, which depicts a serieselectrical coupling of four multi-photoactive-layer PV cells 3810, 3820,3830, and 3840 between a capping anode 3870 and capping cathode 3880.The PV cells 3810, 3820, 3830, and 3840 have a common first outersubstrate 3850, and PV cells 3820 and 3830 have a common second outersubstrate 3851. In addition, a common shared substrate 3855 runs thelength of the series connection, and for each PV cell corresponds to theshared substrate 3710 of the embodiment stylized in FIG. 8A. Each of themulti-photoactive-layer PV cells 3810, 3820, 3830, and 3840 shown in theembodiment of FIG. 8A includes two photoactive layers (e.g., photoactivelayers 3811 and 3812 in PV cell 3810) and two photoelectrodes (e.g.,photoelectrodes 3815 and 3816 in PV cell 3810). A photoactive layeraccording to this and other corresponding embodiments may include anyphotoactive and/or active material as disclosed hereinabove (e.g., firstactive material, second active material, and/or one or more interfaciallayers), and a photoelectrode may include any substrate and/orconductive material suitable as an electrode as discussed herein. Insome embodiments, the arrangement of photoactive layers andphotoelectrodes may alternate from cell to cell (e.g., to establishelectrical coupling in series). For example, as shown in FIG. 8A, cell3810 is arranged between the shared outer substrates according to:photoelectrode-photoactive layer-shared substrate-photoactivelayer-photoelectrode, while cell 3820 exhibits an arrangement whereinthe photoelectrodes and photoactive layers are swapped relative toadjacent cell 3810, and cell 3830 likewise exhibits an arrangementwherein the photoelectrodes and photoactive layers are swapped relativeto adjacent cell 3820 (and therefore arranged similarly to cell 3810).FIG. 8A additionally shows a plurality of transparent conductors (3801,3802, 3803, 3804, 3805, 3806, 3807, and 3808) coupled to portions ofeach of the common substrates 3850, 3851, and 3855 so as to enableelectrical coupling of the PV cells 3810, 3820, 3830, and 3840. Inaddition, FIG. 8A shows electrical coupling of the series of PV cells toa battery (here, Li-Ion battery 3860) in accordance with someembodiments. Such coupling may enable the PV cells to charge the Li-Ionbattery in a similar fashion to the charging of hybrid PV-batteries ofsome embodiments previously discussed. FIG. 8B is an electricalequivalent diagram showing the resulting current flow in the device ofFIG. 8A.

Composite Perovskite Material Device Design

In some embodiments, the present disclosure may provide composite designof PV and other similar devices (e.g., batteries, hybrid PV batteries,FETs, LEDs, nonlinear optics (NLOs), waveguides, etc.) including one ormore perovskite materials. For example, one or more perovskite materialsmay serve as either or both of first and second active material of someembodiments (e.g., active materials 2810 and 2815 of FIG. 5). In moregeneral terms, some embodiments of the present disclosure provide PV orother devices having an active layer comprising one or more perovskitematerials. In such embodiments, perovskite material (that is, materialincluding any one or more perovskite materials(s)) may be employed inactive layers of various architectures. Furthermore, perovskite materialmay serve the function(s) of any one or more components of an activelayer (e.g., charge transport material, mesoporous material, photoactivematerial, and/or interfacial material, each of which is discussed ingreater detail below). In some embodiments, the same perovskitematerials may serve multiple such functions, although in otherembodiments, a plurality of perovskite materials may be included in adevice, each perovskite material serving one or more such functions. Incertain embodiments, whatever role a perovskite material may serve, itmay be prepared and/or present in a device in various states. Forexample, it may be substantially solid in some embodiments. In otherembodiments, it may be a solution (e.g., perovskite material may bedissolved in liquid and present in said liquid in its individual ionicsubspecies); or it may be a suspension (e.g., of perovskite materialparticles). A solution or suspension may be coated or otherwisedeposited within a device (e.g., on another component of the device suchas a mesoporous, interfacial, charge transport, photoactive, or otherlayer, and/or on an electrode). Perovskite materials in some embodimentsmay be formed in situ on a surface of another component of a device(e.g., by vapor deposition as a thin-film solid). Any other suitablemeans of forming a solid or liquid layer comprising perovskite materialmay be employed.

In general, a perovskite material device may include a first electrode,a second electrode, and an active layer comprising a perovskitematerial, the active layer disposed at least partially between the firstand second electrodes. In some embodiments, the first electrode may beone of an anode and a cathode, and the second electrode may be the otherof an anode and cathode. An active layer according to certainembodiments may include any one or more active layer components,including any one or more of: charge transport material; liquidelectrolyte; mesoporous material; photoactive material (e.g., a dye,silicon, cadmium telluride, cadmium sulfide, cadmium selenide, copperindium gallium selenide, gallium arsenide, germanium indium phosphide,semiconducting polymers, other photoactive materials)); and interfacialmaterial. Any one or more of these active layer components may includeone or more perovskite materials. In some embodiments, some or all ofthe active layer components may be in whole or in part arranged insub-layers. For example, the active layer may comprise any one or moreof: an interfacial layer including interfacial material; a mesoporouslayer including mesoporous material; and a charge transport layerincluding charge transport material. In some embodiments, photoactivematerial such as a dye may be coated on, or otherwise disposed on, anyone or more of these layers. In certain embodiments, any one or morelayers may be coated with a liquid electrolyte. Further, an interfaciallayer may be included between any two or more other layers of an activelayer according to some embodiments, and/or between a layer and acoating (such as between a dye and a mesoporous layer), and/or betweentwo coatings (such as between a liquid electrolyte and a dye), and/orbetween an active layer component and an electrode. Reference to layersherein may include either a final arrangement (e.g., substantiallydiscrete portions of each material separately definable within thedevice), and/or reference to a layer may mean arrangement duringconstruction of a device, notwithstanding the possibility of subsequentintermixing of material(s) in each layer. Layers may in some embodimentsbe discrete and comprise substantially contiguous material (e.g., layersmay be as stylistically illustrated in FIG. 1). In other embodiments,layers may be substantially intermixed (as in the case of, e.g., BHJ,hybrid, and some DSSC cells), an example of which is shown by first andsecond active material 2618 and 2620 within photoactive layer 2616 inFIG. 4. In some embodiments, a device may comprise a mixture of thesetwo kinds of layers, as is also shown by the device of FIG. 4, whichcontains discrete contiguous layers 2627, 2626, and 2622, in addition toa photoactive layer 2616 comprising intermixed layers of first andsecond active material 2618 and 2620. In any case, any two or morelayers of whatever kind may in certain embodiments be disposed adjacentto each other (and/or intermixedly with each other) in such a way as toachieve a high contact surface area. In certain embodiments, a layercomprising perovskite material may be disposed adjacent to one or moreother layers so as to achieve high contact surface area (e.g., where aperovskite material exhibits low charge mobility). In other embodiments,high contact surface area may not be necessary (e.g., where a perovskitematerial exhibits high charge mobility).

A perovskite material device according to some embodiments mayoptionally include one or more substrates. In some embodiments, eitheror both of the first and second electrode may be coated or otherwisedisposed upon a substrate, such that the electrode is disposedsubstantially between a substrate and the active layer. The materials ofcomposition of devices (e.g., substrate, electrode, active layer and/oractive layer components) may in whole or in part be either rigid orflexible in various embodiments. In some embodiments, an electrode mayact as a substrate, thereby negating the need for a separate substrate.

Furthermore, a perovskite material device according to certainembodiments may optionally include light-harvesting material (e.g., in alight-harvesting layer, such as Light Harvesting Layer 1601 as depictedin the example PV represented in FIG. 2). In addition, a perovskitematerial device may include any one or more additives, such as any oneor more of the additives discussed above with respect to someembodiments of the present disclosure.

Description of some of the various materials that may be included in aperovskite material device will be made in part with reference to FIG.9. FIG. 9 is a stylized diagram of a perovskite material device 3900according to some embodiments. Although various components of the device3900 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 9 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 3900includes first and second substrates 3901 and 3913. A first electrode3902 is disposed upon an inner surface of the first substrate 3901, anda second electrode 3912 is disposed on an inner surface of the secondsubstrate 3913. An active layer 3950 is sandwiched between the twoelectrodes 3902 and 3912. The active layer 3950 includes a mesoporouslayer 3904; first and second photoactive materials 3906 and 3908; acharge transport layer 3910, and several interfacial layers. FIG. 9furthermore illustrates an example device 3900 according to embodimentswherein sub-layers of the active layer 3950 are separated by theinterfacial layers, and further wherein interfacial layers are disposedupon each electrode 3902 and 3912. In particular, second, third, andfourth interfacial layers 3905, 3907, and 3909 are respectively disposedbetween each of the mesoporous layer 3904, first photoactive material3906, second photoactive material 3908, and charge transport layer 3910.First and fifth interfacial layers 3903 and 3911 are respectivelydisposed between (i) the first electrode 3902 and mesoporous layer 3904;and (ii) the charge transport layer 3910 and second electrode 3912.Thus, the architecture of the example device depicted in FIG. 9 may becharacterized as: substrate-electrode-active layer-electrode-substrate.The architecture of the active layer 3950 may be characterized as:interfacial layer-mesoporous layer-interfacial layer-photoactivematerial-interfacial layer-photoactive material-interfacial layer-chargetransport layer-interfacial layer. As noted previously, in someembodiments, interfacial layers need not be present; or, one or moreinterfacial layers may be included only between certain, but not all,components of an active layer and/or components of a device.

A substrate, such as either or both of first and second substrates 3901and 3913, may be flexible or rigid. If two substrates are included, atleast one should be transparent or translucent to electromagnetic (EM)radiation (such as, e.g., UV, visible, or IR radiation). If onesubstrate is included, it may be similarly transparent or translucent,although it need not be, so long as a portion of the device permits EMradiation to contact the active layer 3950. Suitable substrate materialsinclude any one or more of: glass; sapphire; magnesium oxide (MgO);mica; polymers (e.g., PEN, PET, PEG, polyolefin, polypropylene,polyethylene, polycarbonate, PMMA, polyamide; Kapton, etc.); ceramics;carbon; composites (e.g., fiberglass, Kevlar; carbon fiber); fabrics(e.g., cotton, nylon, silk, wool); wood; drywall; metal; steel; silver;gold; aluminum; magnesium; concrete; and combinations thereof.

As previously noted, an electrode (e.g., one of electrodes 3902 and 3912of FIG. 9) may be either an anode or a cathode. In some embodiments, oneelectrode may function as a cathode, and the other may function as ananode. Either or both electrodes 3902 and 3912 may be coupled to leads,cables, wires, or other means enabling charge transport to and/or fromthe device 3900. An electrode may constitute any conductive material,and at least one electrode should be transparent or translucent to EMradiation, and/or be arranged in a manner that allows EM radiation tocontact at least a portion of the active layer 3950. Suitable electrodematerials may include any one or more of: indium tin oxide or tin-dopedindium oxide (ITO); fluorine-doped tin oxide (FTO); cadmium oxide (CdO);zinc indium tin oxide (ZITO); aluminum zinc oxide (AZO); aluminum (Al);gold (Au); silver (Ag); calcium (Ca); chromium (Cr); magnesium (Mg);titanium (Ti); steel; carbon (and allotropes thereof); doped carbon(e.g., nitrogen-doped); nanoparticles in core-shell configurations(e.g., silicon-carbon core-shell structure); and combinations thereof.

Mesoporous material (e.g., the material included in mesoporous layer3904 of FIG. 9) may include any pore-containing material. In someembodiments, the pores may have diameters ranging from about 1 to about100 nm; in other embodiments, pore diameter may range from about 2 toabout 50 nm. Suitable mesoporous material includes any one or more of:any interfacial material and/or mesoporous material discussed elsewhereherein; aluminum (Al); bismuth (Bi); cerium (Ce); halfnium (Hf); indium(In); molybdenum (Mo); niobium (Nb); nickel (Ni); silicon (Si); titanium(Ti); vanadium (V); zinc (Zn); zirconium (Zr); an oxide of any one ormore of the foregoing metals (e.g., alumina, ceria, titania, zinc oxide,zircona, etc.); a sulfide of any one or more of the foregoing metals; anitride of any one or more of the foregoing metals; and combinationsthereof. In some embodiments, the device illustrated by FIG. 9 may notinclude a mesoporous material layer.

Photoactive material (e.g., first or second photoactive material 3906 or3908 of FIG. 9) may comprise any photoactive compound, such as any oneor more of silicon (in some instances, single-crystalline silicon),cadmium telluride, cadmium sulfide, cadmium selenide, copper indiumgallium selenide, copper indium selenide, copper zinc tin sulfide,gallium arsenide, germanium, germanium indium phosphide, indiumphosphide, one or more semiconducting polymers (e.g., polythiophenes(e.g., poly(3-hexylthiophene) and derivatives thereof, or P3HT);carbazole-based copolymers such as polyheptadecanylcarbazoledithienylbenzothiadiazole and derivatives thereof (e.g., PCDTBT); othercopolymers such as polycyclopentadithiophene-benzothiadiazole andderivatives thereof (e.g., PCPDTBT),polybenzodithiophenyl-thienothiophenediyl and derivatives thereof (e.g.,PTB6, PTB7, PTB7-th, PCE-10); poly(triaryl amine) compounds andderivatives thereof (e.g., PTAA); polyphenylene vinylenes andderivatives thereof (e.g, MDMO-PPV, MEH-PPV), and combinations thereof.In certain embodiments, photoactive material may instead or in additioncomprise a dye (e.g., N719, N3, other ruthenium-based dyes). In someembodiments, a dye (of whatever composition) may be coated onto anotherlayer (e.g., a mesoporous layer and/or an interfacial layer). In someembodiments, photoactive material may include one or more perovskitematerials. Perovskite-material-containing photoactive substance may beof a solid form, or in some embodiments it may take the form of a dyethat includes a suspension or solution comprising perovskite material.Such a solution or suspension may be coated onto other device componentsin a manner similar to other dyes. In some embodiments, solidperovskite-containing material may be deposited by any suitable means(e.g., vapor deposition, solution deposition, direct placement of solidmaterial, etc.). Devices according to various embodiments may includeone, two, three, or more photoactive compounds (e.g., one, two, three,or more perovskite materials, dyes, or combinations thereof). In certainembodiments including multiple dyes or other photoactive materials, eachof the two or more dyes or other photoactive materials may be separatedby one or more interfacial layers. In some embodiments, multiple dyesand/or photoactive compounds may be at least in part intermixed.

Charge transport material (e.g., charge transport material of chargetransport layer 3910 in FIG. 9) may include solid-state charge transportmaterial (i.e., a colloquially labeled solid-state electrolyte), or itmay include a liquid electrolyte and/or ionic liquid. Any of the liquidelectrolyte, ionic liquid, and solid-state charge transport material maybe referred to as charge transport material. As used herein, “chargetransport material” refers to any material, solid, liquid, or otherwise,capable of collecting charge carriers and/or transporting chargecarriers. For instance, in PV devices according to some embodiments, acharge transport material may be capable of transporting charge carriersto an electrode. Charge carriers may include holes (the transport ofwhich could make the charge transport material just as properly labeled“hole transport material”) and electrons. Holes may be transportedtoward an anode, and electrons toward a cathode, depending uponplacement of the charge transport material in relation to either acathode or anode in a PV or other device. Suitable examples of chargetransport material according to some embodiments may include any one ormore of: perovskite material; I⁻/I₃ ⁻; Co complexes; polythiophenes(e.g., poly(3-hexylthiophene) and derivatives thereof, or P3HT);carbazole-based copolymers such as polyheptadecanylcarbazoledithienylbenzothiadiazole and derivatives thereof (e.g., PCDTBT); othercopolymers such as polycyclopentadithiophene-benzothiadiazole andderivatives thereof (e.g., PCPDTBT),polybenzodithiophenyl-thienothiophenediyl and derivatives thereof (e.g.,PTB6, PTB7, PTB7-th, PCE-10); poly(triaryl amine) compounds andderivatives thereof (e.g., PTAA); Spiro-OMeTAD; polyphenylene vinylenesand derivatives thereof (e.g, MDMO-PPV, MEH-PPV); fullerenes and/orfullerene derivatives (e.g., C60, PCBM); carbon nanotubes; graphite;graphene; carbon black; amorphous carbon; glassy carbon; carbon fiber;and combinations thereof. In certain embodiments, charge transportmaterial may include any material, solid or liquid, capable ofcollecting charge carriers (electrons or holes), and/or capable oftransporting charge carriers. Charge transport material of someembodiments therefore may be n- or p-type active and/or semi-conductingmaterial. Charge transport material may be disposed proximate to one ofthe electrodes of a device. It may in some embodiments be disposedadjacent to an electrode, although in other embodiments an interfaciallayer may be disposed between the charge transport material and anelectrode (as shown, e.g., in FIG. 9 with the fifth interfacial layer3911). In certain embodiments, the type of charge transport material maybe selected based upon the electrode to which it is proximate. Forexample, if the charge transport material collects and/or transportsholes, it may be proximate to an anode so as to transport holes to theanode. However, the charge transport material may instead be placedproximate to a cathode, and be selected or constructed so as totransport electrons to the cathode.

As previously noted, devices according to various embodiments mayoptionally include an interfacial layer between any two other layersand/or materials, although devices according to some embodiments neednot contain any interfacial layers. Thus, for example, a perovskitematerial device may contain zero, one, two, three, four, five, or moreinterfacial layers (such as the example device of FIG. 9, which containsfive interfacial layers 3903, 3905, 3907, 3909, and 3911). Aninterfacial layer may include a thin-coat interfacial layer inaccordance with embodiments previously discussed herein (e.g.,comprising alumina and/or other metal-oxide particles, and/or atitania/metal-oxide bilayer, and/or other compounds in accordance withthin-coat interfacial layers as discussed elsewhere herein). Aninterfacial layer according to some embodiments may include any suitablematerial for enhancing charge transport and/or collection between twolayers or materials; it may also help prevent or reduce the likelihoodof charge recombination once a charge has been transported away from oneof the materials adjacent to the interfacial layer. Suitable interfacialmaterials may include any one or more of: any mesoporous material and/orinterfacial material discussed elsewhere herein; Ag; Al; Au; B; Bi; Ca;Cd; Ce; Co; Cu; Fe; Ga; Ge; H; In; Mg; Mn; Mo; Nb; Ni; Pt; Sb; Sc; Si;Sn; Ta; Ti; V; W; Y; Zn; Zr; carbides of any of the foregoing metals(e.g., SiC, Fe₃C; WC); silicides of any of the foregoing metals (e.g.,Mg₂Si, SrSi₂, Sn₂Si); oxides of any of the foregoing metals (e.g.,alumina, silica, titania, SnO₂, ZnO); sulfides of any of the foregoingmetals (e.g., CdS, MoS₂, SnS₂); nitrides of any of the foregoing metals(e.g., Mg₃N₂, TiN, BN, Si₃N₄); selenides of any of the foregoing metals(e.g., CdSe, FeS₂, ZnSe); tellurides of any of the foregoing metals(e.g., CdTe, TiTe₂, ZnTe); phosphides of any of the foregoing metals(e.g., InP, GaP); arsenides of any of the foregoing metals (e.g., CoAs₃,GaAs, InGaAs, NiAs); antimonides of any of the foregoing metals (e.g.,AlSb, GaSb, InSb); halides of any of the foregoing metals (e.g., CuCl,CuI, BiI₃); pseudohalides of any of the foregoing metals (e.g., CuSCN,AuCN₂); carbonates of any of the foregoing metals (e.g., CaCO₃,Ce₂(CO₃)₃); functionalized or non-functionalized alkyl silyl groups;graphite; graphene; fullerenes; carbon nanotubes; any mesoporousmaterial and/or interfacial material discussed elsewhere herein; andcombinations thereof (including, in some embodiments, bilayers,trilayers, or multi-layers of combined materials). In some embodiments,an interfacial layer may include perovskite material. Further,interfacial layers may comprise doped embodiments of any interfacialmaterial mentioned herein (e.g., Y-doped ZnO, N-doped single-wall carbonnanotubes). Interfacial layers may also comprise a compound having threeof the above materials (e.g., CuTiO₃, Zn₂SnO₄) or a compound having fourof the above materials (e.g., CoNiZnO).

A device according to the stylized representation of FIG. 9 may in someembodiments be a PV, such as a DSSC, BHJ, or hybrid solar cell. In someembodiments, devices according to FIG. 9 may constitute parallel orserial multi-cell PVs, batteries, hybrid PV batteries, FETs, LEDS,and/or any other device discussed herein. For example, a BHJ of someembodiments may include two electrodes corresponding to electrodes 3902and 3912, and an active layer comprising at least two materials in aheterojunction interface (e.g., any two of the materials and/or layersof active layer 3950). In certain embodiments, other devices (such ashybrid PV batteries, parallel or serial multi-cell PV tandem devices,etc.) may comprise an active layer including a perovskite material,corresponding to active layer 3950 of FIG. 9. In short, the stylizednature of the depiction of the example device of FIG. 9 should in no waylimit the permissible structure or architecture of devices of variousembodiments in accordance with FIG. 9.

As an example, FIG. 9A illustrates an embodiment of a perovskitematerial device 3900 a having a similar structure to perovskite materialdevice 3900 illustrated by FIG. 9. FIG. 9A is a stylized diagram of aperovskite material device 3900 a according to some embodiments.Although various components of the device 3900 a are illustrated asdiscrete layers comprising contiguous material, it should be understoodthat FIG. 9A is a stylized diagram; thus, embodiments in accordance withit may include such discrete layers, and/or substantially intermixed,non-contiguous layers, consistent with the usage of “layers” previouslydiscussed herein. FIG. 9A includes an active layers 3906 a and 3908 a.One or both of active layers 3906 a and 3908 a may, in some embodiments,include any perovskite photoactive materials described above withrespect to FIG. 9. In other embodiments, one or both of active layers3906 a and 3908 a may include any photoactive material described herein,such as, thin film semiconductors (e.g., CdTe, CZTS, CIGS), photoactivepolymers, dye sensitized photoactive materials, fullerenes, smallmolecule photoactive materials, and crystalline and polycrystallinesemiconductor materials (e.g., silicon, GaAs, InP, Ge). In yet otherembodiments, one or both of active layers 3906 a and 3908 a may includea light emitting diode (LED), field effect transistor (FET), thin filmbattery layer, or combinations thereof. In embodiments, one of activelayers 3906 a and 3908 a may include a photoactive material and theother may include a light emitting diode (LED), field effect transistor(FET), thin film battery layer, or combinations thereof. For example,active layer 3908 a may comprise a perovskite material photoactive layerand active layer 3906 b may comprise a field effect transistor layer.Other layers illustrated of FIG. 9A, such as layers 3901 a, 3902 a, 3903a, 3904 a, 3905 a, 3907 a, 3909 a, 3910 a, 3911 a, 3912 a, and 3913 a,may be analogous to such corresponding layers as described herein withrespect to FIG. 9.

Additional, more specific, example embodiments of perovskite deviceswill be discussed in terms of further stylized depictions of exampledevices. The stylized nature of these depictions, FIGS. 10-21, similarlyis not intended to restrict the type of device which may in someembodiments be constructed in accordance with any one or more of FIGS.10-21. That is, the architectures exhibited in FIGS. 10-21 may beadapted so as to provide the BHJs, batteries, FETs, hybrid PV batteries,serial multi-cell PVs, parallel multi-cell PVs and other similar devicesof other embodiments of the present disclosure, in accordance with anysuitable means (including both those expressly discussed elsewhereherein, and other suitable means, which will be apparent to thoseskilled in the art with the benefit of this disclosure).

FIG. 10 depicts an example device 4100 in accordance with variousembodiments. The device 4100 illustrates embodiments including first andsecond glass substrates 4101 and 4109. Each glass substrate has an FTOelectrode disposed upon its inner surface (first electrode 4102 andsecond electrode 4108, respectively), and each electrode has aninterfacial layer deposited upon its inner surface: TiO₂ firstinterfacial layer 4103 is deposited upon first electrode 4102, and Ptsecond interfacial layer 4107 is deposited upon second electrode 4108.Sandwiched between the two interfacial layers are: a mesoporous layer4104 (comprising TiO₂); photoactive material 4105 (comprising theperovskite material MAPbI₃); and a charge transport layer 4106 (herecomprising CsSnI₃).

FIG. 11 depicts an example device 4300 that omits a mesoporous layer.The device 4300 includes a perovskite material photoactive compound 4304(comprising MAPbI₃) sandwiched between first and second interfaciallayers 4303 and 4305 (comprising titania and alumina, respectively). Thetitania interfacial layer 4303 is coated upon an FTO first electrode4302, which in turn is disposed on an inner surface of a glass substrate4301. The spiro-OMeTAD charge transport layer 4306 is coated upon analumina interfacial layer 4305 and disposed on an inner surface of agold second electrode 4307.

As will be apparent to one of ordinary skill in the art with the benefitof this disclosure, various other embodiments are possible, such as adevice with multiple photoactive layers (as exemplified by photoactivelayers 3906 and 3908 of the example device of FIG. 9). In someembodiments, as discussed above, each photoactive layer may be separatedby an interfacial layer (as shown by third interfacial layer 3907 inFIG. 9). Furthermore, a mesoporous layer may be disposed upon anelectrode such as is illustrated in FIG. 9 by mesoporous layer 3904being disposed upon first electrode 3902. Although FIG. 9 depicts anintervening interfacial layer 3903 disposed between the two, in someembodiments a mesoporous layer may be disposed directly on an electrode.

FIGS. 12-21 are stylized diagrams of perovskite material devicesaccording to some embodiments. Although various components of thedevices are illustrated as discrete layers comprising contiguousmaterial, it should be understood that FIGS. 12-21 are stylizeddiagrams; thus, embodiments in accordance with them may include suchdiscrete layers, and/or substantially intermixed, non-contiguous layers,consistent with the usage of “layers” previously discussed herein. Theexample devices include layers and materials described throughout thisdisclosure. The devices may include a substrate layer (e.g., glass),electrode layers (e.g., ITO, Ag), interfacial layers, which may becomposite IFLs (e.g., ZnO, Al₂O₃, Y:ZnO, and/or Nb:ZnO), a photoactivematerial (e.g. MAPbI₃, FAPbI₃, 5-AVA.HCl: MAPbI₃, and/or CHP: MAPbI₃),and a charge transport layer (e.g., Spiro-OMeTAD, PCDTBT, TFB, TPD,PTB7, F8BT, PPV, MDMO-PPV, MEH-PPV, and/or P3HT).

FIG. 12 is a stylized diagram of a perovskite material device 4400according to some embodiments. Although various components of the device4400 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 12 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 4400includes first and second substrates 4401 and 4407. A first electrode(ITO) 4402 is disposed upon an inner surface of the first substrate4401, and a second electrode (Ag) 4406 is disposed on an inner surfaceof the second substrate 4407. An active layer 4450 is sandwiched betweenthe two electrodes 4402 and 4406. The active layer 4450 includes a firstIFL (e.g., SrTiO₃) 4403, a photoactive material (e.g., MAPbI₃) 4404, anda charge transport layer (e.g., Spiro-OMeTAD) 4405.

FIG. 13 is a stylized diagram of a perovskite material device 4500according to some embodiments. Although various components of the device4500 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 13 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 4500includes first and second substrates 4501 and 4508. A first electrode(e.g., ITO) 4502 is disposed upon an inner surface of the firstsubstrate 4501, and a second electrode (e.g., Ag) 4507 is disposed on aninner surface of the second substrate 4508. An active layer 4550 issandwiched between the two electrodes 4502 and 4507. The active layer4550 includes a composite IFL comprising a first IFL (e.g., Al₂O₃) 4503and a second IFL (e.g., ZnO) 4504, a photoactive material (e.g., MAPbI₃)4505, and a charge transport layer (e.g., Spiro-OMeTAD) 4506.

FIG. 14 is a stylized diagram of a perovskite material device 6100according to some embodiments. Although various components of the device6100 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 14 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 6100includes a substrate (e.g., Glass) 6101. A first electrode (e.g., ITO)6102 is disposed upon an inner surface of the substrate 6101, and asecond electrode (e.g., Ag) 6107 is disposed on top of an active layer6150 that is sandwiched between the two electrodes 6102 and 6107. Theactive layer 6150 includes a composite IFL comprising a first IFL (e.g.,Al₂O₃) 6103 and a second IFL (e.g., ZnO) 6104, a photoactive material(e.g., MAPbI₃) 6105, and a charge transport layer (e.g., Spiro-OMeTAD)6106.

FIG. 15 is a stylized diagram of a perovskite material device 6200according to some embodiments. Although various components of the device6200 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 15 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 6200includes a substrate (e.g., Glass) 6201. A first electrode (e.g., ITO)6202 is disposed upon an inner surface of the substrate 6201, and asecond electrode (e.g., Ag) 6206 is disposed on top of an active layer6250 that is sandwiched between the two electrodes 6202 and 6206. Theactive layer 6250 includes an IFL (e.g., Y:ZnO) 6203, a photoactivematerial (e.g., MAPbI₃) 6204, and a charge transport layer (e.g., P3HT)6205.

FIG. 16 is a stylized diagram of a perovskite material device 6300according to some embodiments. Although various components of the device6300 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 16 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 6300includes a substrate (e.g., Glass) 6301. A first electrode (e.g., ITO)6302 is disposed upon an inner surface of the substrate 6301, and asecond electrode (e.g., Ag) 6309 is disposed on top of an active layer6350 that is sandwiched between the two electrodes 6302 and 6309. Theactive layer 6350 includes a composite IFL comprising a first IFL (e.g.,Al₂O₃) 6303, a second IFL (e.g., ZnO) 6304, a third IFL (e.g., Al₂O₃)6305, and a fourth IFL (e.g., ZnO) 6306, a photoactive material (e.g.,MAPbI₃) 6307, and a charge transport layer (e.g., PCDTBT) 6308.

FIG. 17 is a stylized diagram of a perovskite material device 6400according to some embodiments. Although various components of the device6400 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 17 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 6400includes a substrate (e.g., Glass) 6401. A first electrode (e.g., ITO)6402 is disposed upon an inner surface of the substrate 6401, and asecond electrode (e.g., Ag) 6409 is disposed on top of an active layer6450 that is sandwiched between the two electrodes 6402 and 6409. Theactive layer 6450 includes a composite IFL comprising a first IFL (e.g.,Al₂O₃) 6403, a second IFL (e.g., ZnO) 6404, a third IFL (e.g., Al₂O₃)6405, and a fourth IFL (e.g., ZnO) 6406, a photoactive material (e.g.,5-AVA.HCl:MAPbI₃) 6407, and a charge transport layer (e.g., PCDTBT)6408.

FIG. 18 is a stylized diagram of a perovskite material device 6500according to some embodiments. Although various components of the device6500 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 18 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 6500includes a substrate (e.g., Glass) 6501. A first electrode (e.g., ITO)6502 is disposed upon an inner surface of the substrate 6501, and asecond electrode (e.g., Ag) 6506 is disposed on top of an active layer6550 that is sandwiched between the two electrodes 6502 and 6506. Theactive layer 6550 includes an IFL (e.g., Nb:ZnO) 6503, a photoactivematerial (e.g., FAPbI₃) 6504, and a charge transport layer (e.g., P3HT)6505.

FIG. 19 is a stylized diagram of a perovskite material device 6600according to some embodiments. Although various components of the device6600 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 19 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 6600includes a substrate (e.g., Glass) 6601. A first electrode (e.g., ITO)6602 is disposed upon an inner surface of the substrate 6601, and asecond electrode (e.g., Ag) 6606 is disposed on top of an active layer6650 that is sandwiched between the two electrodes 6602 and 6606. Theactive layer 6650 includes an IFL (e.g., Y:ZnO) 6603, a photoactivematerial (e.g., CHP; MAPbI₃) 6604, and a charge transport layer (e.g.,P3HT) 6605.

FIG. 20 is a stylized diagram of a perovskite material device 6700according to some embodiments. Although various components of the device6700 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 20 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 6700includes a substrate (e.g., Glass) 6701. A first electrode (e.g., ITO)6702 is disposed upon an inner surface of the substrate 6701, and asecond electrode (e.g., Al) 6707 is disposed on top of an active layer6750 that is sandwiched between the two electrodes 6702 and 6707. Theactive layer 6750 includes an IFL (e.g., SrTiO₃) 6703 a photoactivematerial (e.g., FAPbI₃) 6704, a first charge transport layer (e.g.,P3HT) 6705, and a second charge transport layer (e.g., MoOx) 6706.

FIG. 21 is a stylized diagram of a perovskite material device 6800according to some embodiments. Although various components of the device6800 are illustrated as discrete layers comprising contiguous material,it should be understood that FIG. 21 is a stylized diagram; thus,embodiments in accordance with it may include such discrete layers,and/or substantially intermixed, non-contiguous layers, consistent withthe usage of “layers” previously discussed herein. The device 6800includes a substrate (e.g., Glass) 6801. A first electrode (e.g., ITO)6802 is disposed upon an inner surface of the substrate 6801, and asecond electrode (e.g., Al) 6811 is disposed on top of an active layer6850 that is sandwiched between the two electrodes 6802 and 6811. Theactive layer 6850 includes a composite IFL comprising a first IFL (e.g.,Al₂O₃) 6803, a second IFL (e.g., ZnO) 6804, a third IFL (e.g., Al₂O₃)6805, a fourth IFL (e.g., ZnO) 6806, and a fifth IFL (e.g., Al₂O₃) 6807,a photoactive material (e.g., FAPbI₃) 6808, a first charge transportlayer (e.g., P3HT) 6809, and a second charge transport layer (e.g.,MoOx) 6810.

Encapsulant Layer for Thin Film Photovoltaic Device

In some embodiments, a PV device may include one or more encapsulatinglayers. The encapsulating layers may be located proximate to anelectrode layer of the PV device. FIG. 22 illustrates an embodiment of aphotovoltaic device 7100 including encapsulating layers. Althoughvarious components of the device 7100 are illustrated as discrete layerscomprising contiguous material, it should be understood that FIG. 22 isa stylized diagram; thus, embodiments in accordance with it may includesuch discrete layers, and/or substantially intermixed, non-contiguouslayers, consistent with the usage of “layers” previously discussedherein. The photovoltaic device illustrated by Figure Z includes severallayers including: a first substrate 7101, a first electrode 7102, afirst interfacial layer 7103, an active layer 7104, a second interfaciallayer 7105, a second electrode 7106, a non-stoichiometric compound layerZ107, a sealing layer 7108 (also referred to as an encapsulant layer),and a second substrate 7109.

The first substrate 7101 and the second substrate 7109 may be flexibleor rigid. Substrates 7101 and 7109 may be any suitable substratematerial described throughout the instant application, and in particularembodiments may be any suitable substrate material described withrespect to FIGS. 1-21. In some embodiments, only one substrate layer maybe included in a PV device. If two substrates are included, at least oneshould be transparent or translucent to electromagnetic (EM) radiation(such as, e.g., UV, visible, or IR radiation). If one substrate isincluded, it may be similarly transparent or translucent, although itneed not be, so long as a portion of the device permits EM radiation tocontact the active layer 7104. Suitable substrate materials include anyone or more of: glass; sapphire; magnesium oxide (MgO); mica; polymers(e.g., PEN, PET, PEG, polyolefin, polypropylene, polyethylene,polycarbonate, PMMA, polyamide; Kapton, etc.); ceramics; carbon;composites (e.g., fiberglass, Kevlar; carbon fiber) fabrics (e.g.,nylon, cotton, silk, wool); wood; drywall; metal; steel; silver; gold;aluminum; magnesium; concrete; or any other substrate discussed hereinwith respect to FIGS. 6-21 and combinations thereof. In the illustratedembodiment the first substrate 7101 may be impermeable to gases orliquids, or sufficiently thick so as to be effectively impermeable togases or liquids, thereby preventing corrosive or oxidizing materialsfrom reaching layers 7102 through 7108.

Electrode 7102 and electrode 7106 may be any suitable electrode materialdescribed throughout the instant application, and in particularembodiments may be any suitable electrode material described withrespect to FIGS. 1-21. For example, materials suitable for electrodes7102 and 7106 include ITO, FTO, CdO, ZITO, AZO, Al, Au, Cu, Pt, Ca, Mg,Ti, steel, carbon, carbon allotropes (e.g. carbon black, fullerenes,graphene, single wall carbon nanotubes, double wall carbon nanotubes),or any other conductive material. Likewise interfacial layers 7103 and7105 may be any suitable interfacial layer material described throughoutthe instant application, and in particular embodiments may be anysuitable interfacial layer material described with respect to FIGS.1-20. Examples of such materials include oxides, sulfides, or nitridesof Al, Bi, In, Mo, Ni, Si, Ti, V, Nb, Sn, Zn, and combinations thereof(e.g. NiO, Zn₂SnO₄); functionalized or non-functionalized alkyl silyl;groups; and carbon, and carbon allotropes (e.g. carbon black,fullerenes, graphene, single wall carbon nanotubes, double wall carbonnanotubes). In some embodiments, device 7100 may have only oneinterfacial layer, such as only one of interfacial layers 7103 or 7105.In other embodiments, device 7100 may have no interfacial layers.

As with electrode layers 7102 and 7106 and interfacial layers 7103 and7105, active layer 7104 may be any active layer material or photoactivematerial described throughout the instant application, and in particularembodiments may be any suitable material described with respect to FIGS.1-21. In some embodiments active layer 7104 may be a photoactive layer.In other embodiments active layers 7104 may be a light emitting diode(LED), field effect transistor (FET), thin film battery layer, orcombinations thereof. Examples of active layers 7104 materials includeperovskite materials, thin film semiconductors (e.g., CdTe, CZTS, CIGS),photoactive polymers, dye sensitized photoactive materials, fullerenes,small molecule photoactive materials (e.g., bathocuproine, perylenemonoamide, perylene diimide, spiro-OMeTAD, triaryl amine, anthracene,tertracene, pentacene, rubrene, anthradithiophene, quaterthiophene,benzothiophene, TCNQ, ZnPc, CuPc, subPc, TPD, Alq3, Znq2, Zn(BOX)2,BTBT-C5, chlorophyll-a, TIPS-Si), and crystalline and polycrystallinesemiconductor materials (e.g., silicon, GaAs, InP, Ge).

The sealing layer 7108 and the non-stoichiometric compound layer 7107provide protection for layers 7102 through 7106 from the environment inwhich photovoltaic device 7100 resides. Sealing layer 7108 may includean epoxy (e.g., one part epoxies, two part epoxies, epoxy resin, novolacepoxy resin, aliphatic epoxy resin, bisphenol A epoxy resin, bisphenol Fepoxy resin, glycidylamine epoxy resin, amine-based curing epoxy resins,anhydride based curing epoxy resins, thiol-based curing epoxy resins,and phenol-based curing epoxy resins), polymers such as silicone,polypropylene, polybutylene, polyisobutylene, polycarbonate, PMMA, andEVA, glass frit, or combinations thereof. In some embodiments, sealinglayer 7108 may be impermeable to gases such as air, oxygen, water vapor,carbon dioxide, nitrogen, ammonia, and halogens. In other embodimentssealing layer 7108 may have a low permeability to gases such as air,oxygen, water vapor, carbon dioxide, nitrogen, ammonia, and halogens.For example, in certain embodiments sealing layer 7108 may have apermeability equal to or less than 200 g/m² per day at 85 degreesCelsius. In some embodiments, sealing layer 7108 may have a thicknessbetween zero and 100 microns. In other embodiments, sealing layer 7108may have a thickness between 10 microns and 10 millimeters.

Non-stoichiometric compound layer 7107 may be include oxygen containingcompounds in which oxygen is either deficient or in excess with respectto chemical stoichiometry. In certain embodiments, oxide compoundscomprising non-stoichiometric compound layer 7107 may have a formula ofM_(x)O_(y), where M is a metal, O is oxygen, and x and y are realnumbers between 1 and 10. In some embodiments, non-stoichiometriccompound layer 7107 may include SiO, CrO₂, MnO, VO, FeO, CeO, LaO, HfO,ZrO, TiO, AlO, GeO, or combinations thereof. In other embodiments,non-stoichiometric oxide layer 7107 may include a binary, trinary,ternary or greater compound, such as Na_(w)Fe_(x)Ti_(y)O_(z), where w,x, y, and z represent real numbers. For example, a binarynon-stoichiometric compound may have a formula that can be generallyrepresented as M1_(x)M2_(y)O_(z), where M1 is a first metal, M2 is asecond metal, and x, y and z represent real numbers. As furtherexamples, a trinary non-stoichiometric compound may have a formula thatcan be generally represented as M1_(w)M2_(x)M3_(y)O_(z), a ternarycompound may have a formula that can be generally represented asM1_(v)M2_(w)M3_(x)M4_(y)O_(z) and so on. In general a non-stoichiometricoxide refers to any metal oxide that is not the most stable metal oxidethat can be formed for a particular metal or mixture of metals. Table 1shows metal oxides corresponding to different oxidation states forseveral metals. “Stoichiometric” metal oxides are identified with anasterisk in Table 1, and all other metal oxides can be considerednon-stoichiometric.

TABLE 1 Non-Stoichiometric and Stoichiometric Oxides Oxidation StateMetal +1 +2 +3 +4 +5 +6 +7 Al Al₂O AlO *Al₂O₃ N/A N/A N/A N/A Bi Bi₂OBiO Bi₂O₃ BiO₂ *Bi₂O₅ N/A N/A Ce Ce₂O CeO Ce₂O₃ *CeO₂ N/A N/A N/A CoCo₂O CoO *Co₂O₃ N/A N/A N/A N/A Cr Cr₂O CrO Cr₂O₃ CrO₂ Cr₂O₅ *CrO₃ N/ACu Cu₂O *CuO Cu₂O₃ N/A N/A N/A N/A Fe Fe₂O FeO *Fe₂O₃ FeO₂ N/A N/A N/AGe Ge₂O GeO Ge₂O₃ *GeO₂ N/A N/A N/A Hf Hf₂O HfO Hf₂O₃ *HfO₂ N/A N/A N/AIn In₂O InO *In₂O₃ N/A N/A N/A N/A La La₂O LaO *La₂O₃ N/A N/A N/A N/A MnMn₂O MnO Mn₂O₃ MnO₂ Mn₂O₅ MnO₃ *MnO₄ ⁻ Mo Mo₂O MoO Mo₂O₃ MoO₂ Mo₂O₅*MoO₃ N/A Nb Nb₂O NbO Nb₂O₃ NbO₂ *Nb₂O₅ N/A N/A Sb Sb₂O SbO Sb₂O₃ SbO₂*Sb₂O₅ N/A N/A Sc Sc₂O ScO *Sc₂O₃ N/A N/A N/A N/A Si Si₂O SiO Si₂O₃*SiO₂ N/A N/A N/A Sn Sn₂O SnO Sn₂O₃ *SnO₂ N/A N/A N/A Ta Ta₂O TaO Ta₂O₃TaO₂ *Ta₂O₅ N/A N/A Ti Ti₂O TiO Ti₂O₃ *TiO₂ N/A N/A N/A V V₂O VO V₂O₃VO₂ *V₂O₅ N/A N/A Y Y₂O YO *Y₂O₃ N/A N/A N/A N/A Zr Zr₂O ZrO Zr₂O₃ *ZrO₂N/A N/A N/A

Additionally, non-stoichiometric compound layer 7107 may be includesulfur containing compounds in which sulfur is either deficient or inexcess with respect to chemical stoichiometry. In certain embodiments,sulfide compounds comprising non-stoichiometric compound layer 7107 mayhave a formula of M_(x)S_(y), where M is a metal, S is sulfur, and x andy are real numbers between 1 and 10. In some embodiments,non-stoichiometric compound layer 7107 may include SiS, CrS₂, MnS, VS,FeS, CeS, LaS, HfS, ZrS, TiS, AlS, GeS, or combinations thereof. Inother embodiments, non-stoichiometric compound layer 7107 may include abinary, trinary, ternary or greater compound, such asNa_(w)Fe_(x)Ti_(y)S_(z), where w, x, y, and z represent real numbers.For example, a binary non-stoichiometric sulfide compound may have aformula that can be generally represented as M1_(x)M2_(y)S_(z), where M1is a first metal, M2 is a second metal, and x, y and z represent realnumbers. As further examples, a trinary non-stoichiometric sulfidecompound may have a formula that can be generally represented asM1_(w)M2_(x)M3_(y)S_(z), a ternary compound may have a formula that canbe generally represented as M1_(v)M2_(x)M3_(x)M4_(y)S_(z) and so on. Ingeneral a non-stoichiometric sulfide refers to any metal sulfide that isnot the most stable metal sulfide that can be formed for a particularmetal or mixture of metals. Table 2 shows metal sulfides correspondingto different oxidation states for several metals. “Stoichiometric” metalsulfides are identified with an asterisk in Table 2, and all other metaloxides can be considered non-stoichiometric.

TABLE 2 Non-Stoichiometric and Stoichiometric Sulfides Oxidation StateMetal +1 +2 +3 +4 +5 +6 +7 Al Al₂S AlS *Al₂S₃ N/A N/A N/A N/A Bi Bi₂SBiS Bi₂S₃ BiS₂ *Bi₂S₅ N/A N/A Ce Ce₂S CeS *Ce₂S₃ CeS₂ N/A N/A N/A CoCo₂S CoS *Co₂S₃ N/A N/A N/A N/A Cr Cr₂S CrS *Cr₂S₃ CrS₂ Cr₂S₅ CrS₃ N/ACu Cu₂S *CuS Cu₂S₃ N/A N/A N/A N/A Fe Fe₂S FeS *Fe₂S₃ FeS₂ N/A N/A N/AGe Ge₂S GeS Ge₂S₃ *GeS₂ N/A N/A N/A Hf Hf₂S HfS Hf₂S₃ *HfS₂ N/A N/A N/AIn In₂S InS *In₂S₃ N/A N/A N/A N/A La La₂S LaS *La₂S₃ N/A N/A N/A N/A MnMn₂S *MnS Mn₂S₃ MnS₂ Mn₂S₅ MnS₃ MnS₄ ⁻ Mo Mo₂S MoS Mo₂S₃ MoS₂ Mo₂S₅*MoS₃ N/A Nb Nb₂S NbS Nb₂S₃ *NbS₂ Nb₂S₅ N/A N/A Sb Sb₂S SbS Sb₂S₃ SbS₂Sb₂S₅ N/A N/A Sc Sc₂S ScS *Sc₂S₃ N/A N/A N/A N/A Si Si₂S SiS Si₂S₃ *SiS₂N/A N/A N/A Sn Sn₂S SnS Sn₂S₃ *SnS₂ N/A N/A N/A Ta Ta₂S TaS Ta₂S₃ *TaS₂Ta₂S₅ N/A N/A Ti Ti₂S TiS Ti₂S₃ *TiS₂ N/A N/A N/A V V₂S VS *V₂S₃ VS₂V₂S₅ N/A N/A Y Y₂5 YS *Y₂S₃ N/A N/A N/A N/A Zr Zr₂S ZrS Zr₂S₃ *ZrS₂ N/AN/A N/A

Further, non-stoichiometric compound layer 7107 may be include nitrogencontaining compounds in which nitrogen is either deficient or in excesswith respect to chemical stoichiometry. In certain embodiments, nitridecompounds comprising non-stoichiometric compound layer 7107 may have aformula of M_(x)N_(y), where M is a metal, N is nitrogen, and x and yare real numbers between 1 and 10. In some embodiments,non-stoichiometric compound layer 7107 may include SiN, Cr₃N₂, MnN,V₃N₂, Fe₃N₂, Ce₃N₂, La₃N₂, Hf₃N₂, Zr₃N₂, Ti₃N₂, Al₃N₂, GeN, orcombinations thereof. In other embodiments, non-stoichiometric compoundlayer 7107 may include a binary, trinary, ternary or greater compound,such as Na_(w)Fe_(x)Ti_(y)N_(z), where w, x, y, and z represent realnumbers. For example, a binary non-stoichiometric sulfide compound mayhave a formula that can be generally represented as M1_(x)M2_(y)N_(z),where M1 is a first metal, M2 is a second metal, and x, y and zrepresent real numbers. As further examples, a trinarynon-stoichiometric sulfide compound may have a formula that can begenerally represented as M1_(w)M2_(x)M3_(y)N_(z), a ternary compound mayhave a formula that can be generally represented asM1_(v)M2_(x)M3_(x)M4_(y)N_(z) and so on. In general a non-stoichiometricsulfide refers to any metal sulfide that is not the most stable metalsulfide that can be formed for a particular metal or mixture of metals.Table 3 shows metal nitrides corresponding to different oxidation statesfor several metals. “Stoichiometric” metal nitrides are identified withan asterisk in Table 3, and all other metal oxides can be considerednon-stoichiometric.

TABLE 3 Non-Stoichiometric and Stoichiometric Nitrides Oxidation StateMetal +1 +2 +3 +4 +5 +6 +7 Al Al₃N Al₃N₂ *AlN N/A N/A N/A N/A Bi Bi₃NBi₃N₂ *BiN Bi₃N₄ Bi₃N₅ N/A N/A Bo B₃N B₃N₂ *BN N/A N/A N/A N/A Ce Ce₃NCe₃N₂ *CeN Ce₃N₄ N/A N/A N/A Co Co₃N Co₃N₂ *CoN N/A N/A N/A N/A Cr Cr₃NCr₃N₂ *CrN Cr₃N₄ Cr₃N₅ *CrN₂ N/A Cu *Cu₃N Cu₃N₂ CuN N/A N/A N/A N/A FeFe₃N Fe₃N₂ *FeN Fe₃N₄ N/A N/A N/A Ge Ge₃N Ge₃N₂ GeN *Ge₃N₄ N/A N/A N/AHf Hf₃N Hf₃N₂ *HfN Hf₃N₄ N/A N/A N/A In In₃N In₃N₂ *InN N/A N/A N/A N/ALa La₃N La₃N₂ *LaN N/A N/A N/A N/A Mn Mn₃N *Mn₃N₂ MnN Mn₃N₄ Mn₃N₅ MnN₂*MnN₃ ²⁻ Mo Mo₃N Mo₃N₂ *MoN Mo₃N₄ Mo₃N₅ MoN₂ N/A Nb Nb₃N Nb₃N₂ *NbNNb₃N₄ Nb₃N₅ N/A N/A Sb Sb₃N Sb₃N₂ *SbN Sb₃N₄ Sb₃N₅ N/A N/A Sc Sc₃N Sc₃N₂*ScN N/A N/A N/A N/A Si Si₃N Si₃N₂ SiN *Si₃N₄ N/A N/A N/A Sn Sn₃N Sn₃N₂SnN *Sn₃N₄ N/A N/A N/A Ta Ta₃N Ta₃N₂ *TaN Ta₃N₄ Ta₃N₅ N/A N/A Ti Ti₃NTi₃N₂ *TiN Ti₃N₄ N/A N/A N/A V V₃N V₃N₂ *VN V₃N₄ V₃N₅ N/A N/A Y Y₃N Y₃N₂*YN N/A N/A N/A N/A Zr Zr₃N Zr₃N₂ *ZrN Zr₃N₄ N/A N/A N/A

Non-stoichiometric oxides may also exist as charge species, such as NbO₃⁻, TiO₃ ²⁻, and SbO₂ ⁻. Likewise, non-stoichiometric sulfides andnitrides may exist as charge species, such as VS₃ ²⁻, Si₂N₆ ¹⁰⁻. In someembodiments, non-stoichiometric oxides, sulfides and nitrides may alsoinclude mixed valence species such as Fe₃O₄, Mn₃O₄, mixed metal species,such as CuFeO₂, Co₂S₃, Fe₂S₃, FeN and combinations thereof.Additionally, some non-stoichiometric oxides can exist as hydrated formsthat may contain hydroxide species such as Sn(OH)₂. In some embodiments,non-stoichiometric compound layer 7107 may have a thickness between zeroand ten microns. In other embodiments, non-stoichiometric compound layer7107 may have a thickness between 1 and 50 nanometers. In someembodiments, non-stoichiometric compound layer 7107 may have a thicknessbetween 1 and 10 nanometers.

Non-stoichiometric compound layer 7107 may be able to absorb or entrapgases such as oxygen, water vapor, carbon dioxide, ammonia, and halogensthrough physisoprtion, adsorption, or a chemical reaction. For example,a non-stoichiometric compound layer 7107 composed of SiO may react withoxygen that is able to diffuse through sealing layer 7108 to form SiO₂,effectively preventing oxygen from reaching layer 7102 through 7106 andpreventing oxidation damage to the electrode layers, interfacial layers,and active layer of photovoltaic device 7100. By absorbing, reactingwith, or otherwise entrapping any substances that are able to movethrough sealing layer 7108, non-stoichiometric compound layer 7107prevents those substances from damaging the photovoltaic device. In someembodiments, a reaction between the non-stoichiometric compound layer7107 may passivate a portion of the non-stoichiometric compound layer7107. For example, as an SiO non-stoichiometric oxide layer 7107 reactswith oxygen to form SiO₂, the rate of oxygen diffusing into thenon-stoichiometric oxide layer 7107 may be slowed down by the portion ofnon-stoichiometric oxide layer Z107 that has reacted with the oxygen toform SiO₂. Examples of reactions between non-stoichiometric oxide layer7107 and oxygen are shown below.

2SiO+O₂--->2SiO₂  1)

4CoO+O₂--->2Co₂O₃  2)

Sb₂O₃+O₂--->Sb₂O₅  3)

2Ce₂O₃+O₂--->4CeO₂  4)

A non-stoichiometric oxide layer and an sealing layer, such as thosedescribed above with respect to FIG. 22 may be placed proximate to anyelectrode illustrated in FIGS. 1-21. For example, a non-stoichiometricoxide layer and an sealing layer may be deposited between Pt/FTO layer1502 and Glass layer 1501 and/or between FTO layer 1506 and Glass layer1507 of FIG. 1. As a further example, a non-stoichiometric oxide layerand an encapsulant layer may be used in a device having multipleinterfacial and active layers such as device 3900 illustrated by FIG. 9.In an embodiment of such a device, a non-stoichiometric oxide layer andan encapsulant layer may be deposited between electrode 2 3912 andsubstrate 2 2913 and/or between electrode 1 3902 and substrate 1 3901.Non-stoichiometric compound layer 7107 may be deposited by a variety ofmethods, including but not limited to spin coating, slot-die printing,chemical vapor deposition, thermal evaporation, sputtering, atomic layerdeposition, extrusion, and gravure printing. Non-stoichiometric oxidedeposition may further occur under a controlled atmosphere. For example,non-stoichiometric oxide deposition may occur under dry nitrogen, argon,helium, neon, or carbon oxide atmospheres. In some embodiments, thedeposition atmosphere may include a controlled amount of water vaporranging, a vacuum (e.g., less than 760 Torr), or a high vacuum (e.g.,less than 10⁻⁶ Torr).

In other embodiments a photovoltaic device may include sealing layersand non-stoichiometric compound layers on both sides of the photovoltaicdevice. FIG. 23 illustrates an embodiment of a photovoltaic device 7200,similar to photovoltaic device 7100 illustrated by FIG. 22, thatincludes additional encapsulating layers. Photovoltaic device 7200,includes a sealing layer 7208 a and non-stoichiometric compound layer7207 a disposed between substrate 1 7201 and electrode 1 7202, inaddition to sealing layer 7208 b and non-stoichiometric compound layer7207 b disposed between substrate 2 7209 and electrode 2 7206. Sealinglayers 7208 a and 7208 b may comprise any materials described here inwith respect to sealing layer 7108 illustrated by FIG. 22. Likewise,non-stoichiometric compound layers 7207 a and 7207 b may comprise anymaterials described here in with respect to non-stoichiometric compoundlayer 7108 illustrated by FIG. 22.

Further, in some embodiments, a photovoltaic device may include one ormore non-stoichiometric compound layers between layers of the device.For example, a photovoltaic device may include a non-stoichiometriccompound layer between an interfacial layer and an active layer (e.g.photoactive layer, battery layer, or semi-conductor layer as describedherein), between an interfacial layer and an electrode, or between anactive layer and an electrode. FIG. 24 illustrates an embodiment of aphotovoltaic device 7300, similar to photovoltaic device 7200illustrated by FIG. 23 and photoactive device 7100 illustrated by FIG.22. that includes a non-stoichiometric compound layer 7307 c disposedbetween active layer 7304 and interfacial layer 7303. In such anembodiment, non-stoichiometric compound layer 7307 c may be sufficientlythin to allow for charge transport between active layer 7304 andinterfacial layer 7303. For example, in some embodiments,non-stoichiometric compound layer 7307 c may be between 0.5 and 20nanometers thick. In further embodiments, non-stoichiometric compoundlayer 7307 c may be between 0.5 and 5 nanometers thick. In yet furtherembodiments, non-stoichiometric compound layer 7307 c may be between 0.5and 1 nanometer thick.

Therefore, the present invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Furthermore, no limitations areintended to the details of construction or design herein shown, otherthan as described in the claims below. It is therefore evident that theparticular illustrative embodiments disclosed above may be altered ormodified and all such variations are considered within the scope andspirit of the present invention. In particular, every range of values(of the form, “from about a to about b,” or, equivalently, “fromapproximately a to b,” or, equivalently, “from approximately a-b”)disclosed herein is to be understood as referring to the power set (theset of all subsets) of the respective range of values, and set forthevery range encompassed within the broader range of values. Also, theterms in the claims have their plain, ordinary meaning unless otherwiseexplicitly and clearly defined by the patentee.

1. A photovoltaic device comprising: a first electrode; a secondelectrode; an active layer disposed at least partially between the firstand second electrodes, the active layer comprising a photoactivematerial; an interfacial layer disposed at least partially between thefirst and second electrodes; a reactive non-stoichiometric oxide layerdisposed at least partially between and in contact with one of the firstor second electrodes and an encapsulant layer.
 2. The photovoltaicdevice of claim 1, wherein the reactive non-stoichiometric oxide layercomprises one or more compounds each selected from the group consistingof SiO, CrO₂, MnO, VO, FeO, CeO, LaO, HfO, ZrO, TiO, AlO, GeO, orcombinations thereof.
 3. The photovoltaic device of claim 1, wherein thereactive non-stoichiometric oxide layer comprises a compound having theformula MxOy, wherein M comprises one or more metals, x represents areal number between 1 and 10, and y represents a real number between 1and
 10. 4. The photovoltaic device of claim 1, wherein the reactivenon-stoichiometric oxide layer comprises a compound having the formulaM_(w)M′_(x)M″_(y)O_(z), wherein M, M′ and M″ each comprise a metal. 5.The photovoltaic device of claim 1, wherein the encapsulant layercomprises one or more compounds each selected from the group consistingan epoxy, silicone, polypropylene, polybutylene, polyisobutylene,polycarbonate, PMMA, EVA, glass, or combinations thereof.
 6. Thephotovoltaic device of claim 1, wherein the reactive non-stoichiometricoxide layer comprises SiO.
 7. The photovoltaic device of claim 1,wherein the photoactive material comprises a perovskite material.
 8. Thephotovoltaic device of claim 1, wherein the one or more interfaciallayers comprise an oxide, sulfide, or nitride of one or more metalsselected from the group consisting of Al, Bi, In, Mo, Ni, Si, Ti, V, Nb,Sn Zn and combinations thereof.
 9. The photovoltaic device of claim 1,wherein the reactive non-stoichiometric oxide layer has a thicknessequal to or greater than one nanometer and less than or equal to fiftynanometers.
 10. The photovoltaic device of claim 1, wherein theencapsulant layer has a thickness equal to or greater than ten micronsand less than or equal to ten millimeters.
 11. The photovoltaic deviceof claim 1, wherein the reactive non-stoichiometric oxide layercomprises one or more compounds selected from the group consisting ofFe₃O₄, CuFeO₂, Mn₃O₄.
 12. The photovoltaic device of claim 1, whereinthe reactive non-stoichiometric oxide layer comprises SiO, and theencapsulant layer comprises PMMA.
 13. The photovoltaic device of claim1, wherein the reactive non-stoichiometric oxide layer comprises SiO,the encapsulant layer comprises PMMA, and the first and second electrodelayers comprise ITO.
 14. A device comprising: a first electrode; asecond electrode; an active layer disposed at least partially betweenthe first and second electrodes; a reactive non-stoichiometric oxidelayer disposed at least between and in contact with one of the first orsecond electrodes and an encapsulant layer.
 15. The device of claim 15,wherein the reactive non-stoichiometric oxide layer comprises one ormore compounds each selected from the group consisting of SiO, CrO₂,MnO, VO, FeO, CeO, LaO, HfO, ZrO, TiO, AlO, GeO, or combinationsthereof.
 16. The device of claim 15, wherein the reactivenon-stoichiometric oxide layer comprises a compound having the formulaMxOy, wherein M comprises one or more metals, x represents a real numberbetween 1 and 10, and y represents a real number between 1 and
 10. 17.The device of claim 15, wherein the reactive non-stoichiometric oxidelayer comprises a compound having the formula M_(w)M′_(x)M″_(y)O_(z),wherein M, M′ and M″ each comprise a metal.
 18. The device of claim 15,further comprising an encapsulant layer disposed in contact with thereactive non-stoichiometric oxide layer, wherein the encapsulant layercomprises one or more compounds each selected from the group consistingof an epoxy, silicone, polypropylene, polybutylene, polyisobutylene,polycarbonate, PMMA, EVA, glass, or combinations thereof.
 19. The deviceof claim 15, wherein the reactive non-stoichiometric oxide layercomprises SiO.
 20. The device of claim 15, wherein the active layercomprises a one or more transistors.
 21. The device of claim 15, whereinthe one or more interfacial layers comprise an oxide, sulfide, ornitride of one or more metals selected from the group consisting of Al,Bi, In, Mo, Ni, Si, Ti, V, Nb, Sn, Zn and combinations thereof.
 22. Thedevice of claim 15, wherein the reactive non-stoichiometric oxide layerhas a thickness equal to or greater than one nanometer and less than orequal to fifty nanometers.
 23. The device of claim 18, wherein theencapsulant layer has a thickness equal to or greater than ten micronsand less than or equal to ten millimeters.
 24. The device of claim 15,wherein the reactive non-stoichiometric oxide layer comprises one ormore compounds each selected from the group consisting of Fe₃O₄, CuFeO₂,and Mn₃O₄.
 25. The device of claim 18, wherein the reactivenon-stoichiometric oxide layer comprises SiO, and the encapsulant layercomprises PMMA.
 26. The device of claim 18, wherein the reactivenon-stoichiometric oxide layer comprises SiO, the encapsulant layercomprises PMMA, and the first and second electrode layers comprise ITO.27. A photovoltaic device comprising: a first electrode; a secondelectrode; an active layer disposed at least partially between the firstand second electrodes, the active layer comprising a photoactivematerial; an interfacial layer disposed at least partially between thefirst and second electrodes; a first reactive non-stoichiometric oxidelayer disposed at least partially between and in contact with the firstelectrode and a first encapsulant layer; and a second reactivenon-stoichiometric oxide layer disposed at least partially between andin contact with the second electrode and a second encapsulant layer. 28.The device of claim 27, wherein the first and second reactivenon-stoichiometric oxide layers comprise one or more compounds eachselected from the group consisting of SiO, CrO₂, MnO, VO, FeO, CeO, LaO,HfO, ZrO, TiO, AlO, GeO, or combinations thereof.
 29. The device ofclaim 27, wherein the first and second reactive non-stoichiometric oxidelayers comprise a compound having the formula MxOy, wherein M comprisesone or more metals, x represents a real number between 1 and 10, and yrepresents a real number between 1 and
 10. 30. The device of claim 27,wherein the first and second reactive non-stoichiometric oxide layerscomprise SiO.